To get good shots of animals and birds, you will have to learn to be quick in setting up and framing your shots. Waiting until you get out in the wilderness to learn these tricks is not a good idea. What I found to be very helpful was practicing on my cats and on birds in my yard or local parks. You learn to anticipate their behavior and react fast to get the good shots. Here are some tips on how to get the best shots of animals and birds in the wild.
Practice taking shots of moving targets. Learning how to pan moving targets will allow you to take dramatic photographs with a sense of speed.
Keep your camera handy and set up for unexpected encounters. Make sure you have fully charged camera batteries and plenty of film or memory.
Before you go into an area, read up on what kinds of animals and birds are commonly found there. Learn all you can about these animals and birds. This will help you know where to look to find them and what kinds of behavior to expect.
Learn to walk and move quietly and practice freezing your position so that your presence is not startling or threatening to the animal.
Learn to be observant of everything around you using all your senses. With a little practice, you will gain the ability to be aware of small movements, unusual colors or sounds, even smells that can tip you off to the presence of an animal or bird even when they are well camouflaged. I cannot believe how many times I've watched people walk right by wildlife without noticing them. Hiking with an awareness of your surroundings enhances your experience immeasurably.
In the wild, telephoto lenses are basically a must. This brings you in a little closer without scaring the animals. The use of a tripod is not always mandatory, if you have enough light you will be able to shoot at a fast shutter speed to eliminate shake. Some telephoto lens have vibration reduction technology but are considerably more expensive.
When you photograph animals and birds, make sure the focus is sharpest on their eyes.
Shoot small animals from a lower angle.
The best times of the day for viewing and photographing wildlife are early in the mornings and just before dark. This is when wildlife is usually most active and the light is the most dramatic.
Try to keep the sun at your back so that the light falls directly on your subject.
Using all these tips will help you improve your nature photography. The very most important thing is practice, practice, practice and don't forget to enjoy yourself!