Assuming that the subject you want to photograph can be found at several locations, there are a number of other criteria that might help you select a site to photograph:

1. Convenience - the easier it is to get there the more time you have to take pictures.
2. Legality - do you have permission to be there?  You might need to check with a landowner to get permission to photograph on private property.
3. Access - how close can you get with a car? How difficult is the terrain?  How much of your equipment will you be able to haul in (and then back out)?
4. Topography - how does slope and tree cover affect the light at the time you will be there to photograph?  You won't have a lot of light, for instance, on the west slope of a mountain in the morning.
5. Safety - are there natural or human threats at the site?  Active volcanoes aren't the safest place to be, nor is an isolated alley in a bad part of town when you are alone and carrying expensive camera gear.
6. Crowds - it's tough to photograph birds in a city park when there are a lot of people running around playing frisbee with their dogs.  You might want a little more isolation.  On the other hand, a park full of dogs and their owners is probably pretty safe - you have to determine the best balance yourself.

Some possible public land sites:

1. Parks - from city to national, these are often the best places to go.  If you will be going to a number of national parks, federal wildlife areas, etc. inquire as to the availability of a Golden Eagle Pass which will get you into all of them for free (after you buy the pass).
2. National and State wildlife and hunting lands - these can be very good places to go, at least outside of hunting season.  They are not as well publicised.
3. River and beach access points - even in the most developed areas, there is often a place where a public accessway is maintained.  On the coasts, you cannot actually own land under the ocean, so if you don't mind wading or swimming you can get to just about any site. The same often applies to rivers as well, but riparian law varies from state to state, so be careful.  Regardless of legal precedent, the person with the shotgun or badge makes the rules.
4. Bridges - state and local governments normally own a right of way along a road that includes the land under a bridge (giving you access to the stream).  Park your car carefully off the road, and don't cross any fences.
5. Pipeline and power right-of-ways - while not public lands, under some circumstances the companies operating these utilities may give you permission to walk on their right-of-ways.  There should be a phone number to call located on the markers for the right-of-way.
6. Nature preserves - technically not parks, these are managed by governmental (and non-governmental) agencies for the wildlife, not for people.  Access to many of these is strictly limited.  However, if anyone is likely to gain access, it is a photographer, since it is clear that you are not there to damage the habitat.  Always get permission from both the central agency and their local caretaker.  If you do frequent preserves run by non-profit agencies, by all means support them by volunteering, joining them, or sending a donation.
7. Corporate areas - some companies with large land holdings, such as coal and lumber companies allow access to their sites.  In some cases you need to get permission, in others signs on the property inform you as to the rules of access. 

Planning and Packing

Before you set off, there are a number of tasks that you need to do.  Whether for a trip to the local park or an expedition to Alaska, you should consider all of the following items:

1. What are you going to take photos of?  Make a list of the things you expect to find and hope to find.  Evaluate your portfolio and identify areas where it is weak, and consider whether you will be able to strengthen those weak areas on this trip.  
2. Estimate the type and amount of film you will need.  If the weather will be cloudy or you will be doing a lot of extreme telephoto work, you may want to pack more fast film; if you will be taking mostly scenics in the desert you might want additional slow film.  For extended trips, I budget 5 rolls per day - including travel days.  On a good day, Ican easily go through 10 rolls.  For local trips, I take at least 5 rolls.  Check your stock of film and order more so that it will arrive before you go.
3. Learn about the site.  Check it out on the web, talk to people who have been there, examine guidebooks.  Birders in particular have been good about publishing guides to birdwatching sites - there are regional Peterson guides for this, and many state birding associations have more local guides.  Know what to expect before you get there, know where to go to get food, gas, car repairs, and, of course, CAMERA BATTERIES & FILM!
4. Obtain a map, preferably a topographic map, of the site.
5. Check the weather.  You need to know how to dress and whether it will be cloudy.  Watch the weather channel for several days in advance so you know what type of weather the area is getting and what weather systems are on the way.
6. When will it get light?  For a local area, just watch the weather segment of your local news or read the local paper.  For more distant sites, check almanacs or use the Geoclock program (shareware, search for it on the web) to determine sunup and sunset times for the locale you will visit.  If you will be on the coast, it's also good to determine the local tides as well.
7. Continue to update this information, particularly the weather, as the trip approaches.  Listen to a local radio station on the drive to the site for last-minute weather updates.

Once you have done the background research, it's time to get ready.  Decide what personal equipment and camera equipment you will need, write a list, check out all the equipment, and pack it for the trip.  Click below to bring up checklists you can print out and modify to your equipment:

Use sense when selecting equipment - there is no need to take GPS or firestarting equipment for a walk to the local park.  On the other hand, if you are allergic to bee-stings you probably should have you injection kit handy.  Of course, if you are camping, there will be still more equipment needed. 

Do not depend on devices like a cell phone or GPS to keep you out of trouble or get you out of it.  Technological devices have a tendency to fail at the most inopportune times. Be sure you have the skills necessary to survive in the wilderness (if that's where you're going) and find your way out.

Choose your camera gear with care.  Certainly take all the equipment you think you will need, but don't overburden yourself.  Carry your equipment in well-organized bags that are easy to carry, easy to locate the gear in, and which can protect the equipment from falls, drops and water.  If you won't be far from your car, you might want to leave some items there and return to the car if you need to.

As you pack your equipment, give it a checkout:

1. If the camera is unloaded, open the back and make sure the film path is clear.  Close the back and make several test "exposures" to be sure the shutter is working.  Make sure the camera "sounds right".  Load the camera with film if you want to.
2. Check the camera's battery. Pack a spare.
3. Turn the camera off.
4. Remove the lens and gently blow any dust off the mirror (swallow first).  Replace the lens. Gently wipe off any dust from the other areas of the camera.   Use a lens cleaner, if needed on the viewfinder.
5. Check each lens for dirt and clean if necessary.  Click here for instructions.
6. Be sure each flash is clean, including the contacts.  Turn the flash on and fire a test flash.  Check the battery recycle time. Pack spare batteries.
7. Make sure all accessories are in working condition.  
8. Check the tripod to make sure all moving parts are clean of dirt and grit.  Pay particular attention to the threads that screw into the camera.
9. Make sure that your camera bags are clean (inside and out).  Be sure all small compartments are closed and that all fasteners work.
10. With your bags packed, make sure that all equipment is secure and that nothing is rattling or liable to fall out.

Using Time Effectively

Photography is a 4-dimensional game.  You have to be in the right place at the right time.  The right time means the right season, the time of day when the organism is active, when the light is right, and when the weather is cooperating.  Needless to say, this doesn't always happen, but when it does the results are spectacular.  To maximize the chances of it happening, here are some tips:

1. Plan ahead as described above.
2. When you get to the site, look for any obvious organisms (i.e. if a bear is standing there take pictures of it!)
3. Lacking any obvious subject, head for an area where the light is right.  Look for what Julie Zickefoose calls "butter light" - the red and yellow sunlight or early morning and early evening.
4. Photograph motile animals before turning your attention to the plants - they aren't going anywhere.
5. Ditto the mountains - they won't go anywhere, but keep an eye on them for changing light or cloud conditions.
6. If you bypass an immobile subject, be sure to note where it is so you can come back.
7. If the subject isn't "perfect" in terms of its physical appearance, the lighting, its position relative to you, or its behavior, take a few "insurance shots" and move on.  Come back later if you don't find any better subjects.
8. Move around the area to take advantage of the rising (or setting sun).

Photographing Ecosystems

Documenting an ecosystem or habitat is a tricky business.  Part of it can be accomplished by photographing as many of the individual types of organisms as you can.  But an album of disconnected organisms does not capture the essence of the habitat they were living in.  To bridge this gap, you need some pictures that capture larger clumps of the ecosystem.

Look for opportunities to do this as you explore a site.  Some tricks you might employ include:

1. Looking for organisms interacting - a bird nesting in a tree; a hawk eating a prairie dog.
2. Look for pictures that tell a story about the ecosystem.  A classic visual cliche is the old picture of a cow skull on the dust desert floor.  
3. Use a wide-angle lens to get as much of the ecosystem into view as possible.
4. Get up high - on a hill, tower, mountain, plane, dirigible, space shuttle, whatever to get a different view.  Don't neglect the opportunity to photograph a habitat while flying into or out of the area.  Always take a window seat.
5. Pick out essential organisms - indicator organisms - and be sure to photograph them.  You can't have pictures of the Arctic without a picture of a polar bear; likewise a picture of the prairie is incomplete without grass and bison, and the taiga must be represented by conifers.
6. At the same time, look for lesser-known inhabitants of the habitat so that you can tell a new, different story.  How about dung beetles behind all those bison?  Or the ants that make huge mounds in the taiga?

Photographing Plants

It might seem that plants would be easier to photograph than animals, seeing as how they don't move.  Well, plants pose unique challenges of their own:

Photographing Animals

Many of the comments about plants also apply to animals as well.  Many animals, however, have the ability to move, and this complicates matters some.  Other animals have the ability to bite, bark, sting, maul, gore, invenomate, regurgitate, defecate, urinate, and just get huffy with you.  You need to be a bit more flexible to work with animals.  Again, a few hints might help:

1. Learn the habits and habitats of the animals you are trying to photograph.  You will be able to better predict where they will be and when they will be there.
2. As you move, have a medium telephoto zoom (100-300mm) handy in case you need to make a grab shot.  Set your camera on aperture priority, and keep the lens wide open.  This way, the camera will select the fastest possible shutter speed.
3. Learn the value of the "insurance shot".  This ensures that you will get something on film.  As soon as you see an animal, stop and take a picture of it with the lens you have on your camera.  
4. Change to a more appropriate lens and slowly work your way to a better shot.  Get the sun behind you and approach slowly.  If the animal seems to get jumpy, stop.
5. Learn the signs that an animal is getting ready to flee - or take your head off.  Most animals have a "comfort zone", you can move up to that zone but no closer.
6. Some animals will flee a short distance, then stop.  You can then try to approach again; sometimes after several of these attempts the animal will become habituated to your presence and will allow you to get really close.  Other animals will just run, fly or swim off.
7. Know which sense the animal depends on to warn of danger.  Always be as quiet as you can.  Some animals will only flee when they smell you; stay downwind of them.  Others are more sensitive to sight; stay out of sight.
8. Use a blind or your car to get close.  Many animals living near roads will ignore anyone in a car.  You can get window mount clamps for your tripod head, or you can set the tripod up in the car.  A blind can be as simple as a tarp or as fancy as a permanent building.  Turkey and  hunters have similar problems getting close to their quarry; check sporting catalogues for blinds, tree stands, scent-free clothing, ghilly suits, etc.
9. Animals at parks may be particularly used to people and particularly tame.
10. Look for places where animals congregate - salt licks, water holes, mating grounds, restaurant parking lots, garbage dumps.
11. In many cities there is a park called a zoo which seems to attract more exotic animals than you would normally see in other city parks.  Actually, many native animals, particularly birds, flock to these parks as well.
12. Use long lenses with dangerous animals.  Any animal that is bigger than you are is by definition dangerous, with the exception of dolphins, manatees, and poodles.
13. When you find an unusually tame animal, shoot as much film as you can.  Eventually, these will be your real "keeper" shots.

Now that you're ready to take a picture, you might want to review some specialized techniques: