Red wattled lapwing through grass
Most wildlife: birds, insects, snakes, mammals, will react very quickly to motion. What this means is if you make sudden quick jerky movements, you will be noticed and whatever you are shooting will run away. So learn to move slowly, smoothly. I have found this can require quite a bit of strength and agility, so develop those. And oodles of patience, the hardest muscle to build.
Even if you have been discovered, staying motionless afterwards makes animals forget about you and continue with their life after sometime.
Camouflage clothing is artform, no really, look at what the military has been upto with it. It's useful, certainly you can't be wearing bright white or red clothes and expect to go unnoticed. Dress appropriately to the environment you expect to be in. Quiet shoes, comfortable shoes, discreet colours. If you can camo your equipment as well.
This is actually one of the reasons I dislike shooting with other people. Silence obviously keeps attention away from you, but it does a second thing. If you are quiet you'll hear other things, you'll find subjects to photograph or you'll notice that elephant sneaking up behind you. So leave the Ipod behind ok? Shootings safer and more productive that way.
No really. Particularly with mammals, strong odours, deodorant/perfume is a guaranteed way of not getting any shots. Leave your vanity behind.
Mongoose cub eating temple offerings
The classic wildlife mode of shooting off course is to stay in one place and let animals come to you, hide photography. Get a hide, a camo net and stay. Hedge your chances of getting close to something by setting up a hide near a resource an animal needs (water, food, salt lick, mating grounds) or a place an animal inhabits (nest, den, etc). As I said knowledge is everything. Also oodles of patience, and all of the above. Some people also use bait, I haven't yet, although I have sort of used food others have set out.
This is a different kind of photography altogether. All but sit still applies, well actually sit still, move, sit still, move, you get the idea? Use the terrain, hide behind things, plants, stones, etc. Stay out of direct line of eyesight of your quarry. Use zig-zag or round about approaches to it. When there isn't anything to hide behind squat on the ground and move bent down.
Keep your camera close to shoulder high while approaching. Its hard to do this undetected when you're close. (Any other ideas here?)
Remember your limits, never get too close, you'll loose your shot or worse get bitten, gored or killed. When in doubt err on the side of caution.
Believe it or not animals do get used to you. Wear the same or very similar clothes. Be unobtrusive and completely non-threatening. Keep returning to the place that your quarry is, it will maybe eventually accept you as part of the landscape. True of birds and mammals, insects and reptile, probably not.
f5.6 and don't be there!
Camera traps are cool, and potentially expensive. So using remotes is also an option, stay close enough so you can trigger and guard your gear.
PS: the first 2 images link to my new Flickr gallery, following Strobist ideas on the service. Will see how it pans out.