How to Take a Good Snake Picture
A lot of people don't like snakes, but I do. Which isn't to say that they don't startle me when I stumble upon them. But when neither snake or I panic upon encountering each other, I take the opportunity to try and get a good picture.
Snakes are usually found coiled on the ground. This position means that you're going to have a hard time getting all of a snake's body in focus unless you step down your camera's aperture. But doing so means the shutter speed will be slow unless your subject happens to be very well lit. A slow shutter speed is still good enough to capture an unmoving snake except that you'll introduce some blurriness from your body and hand movements, slight as they may be.
More often than not, I try to get the snake's head and eyes in focus and don't worry about what happens to the rest of the body. Even that is tough to do as the snakes I encounter are pretty uniform in color offering little contrast for my camera's auto-focus to detect.
One thing that will frustrate you is that snakes sometimes aren't interested in having their picture taken. In such cases they'll simply slither off in to the brush where it is next to impossible to follow them. To counter this, you may wish to position yourself in between the snake and its expected escape route. This can sometimes buy you some time in firing off an extra shot or two.