Plan the shot at home
Best, you plan the shot at home and prepare your backpack with all items you need for the photo you want to take.
The closer the better
Finding a way to be as close as possible to the animal without disturbing it and without feeding it. Doesn't apply to dangerous animals and hazardous environment! The animal should fill at least 1/6th of the frame.
Get dirty or wet or both
To take a photo lay or kneel on the ground. A low angle versus top down shots are nicer in most situations. Then get closer by crawling towards the animal while taking photos. Looks funny but who cares?