Often animals will be more scared of you than you are of them. They are used to having to fight for survival, and we look big and mean to any animal, except maybe sharks, elephants etc. Generally though, anything smaller than us will be afraid of us and will only attack if they think we are weak.
I don't believe it is good enough to merely stand your ground. A lot of animals enjoy fighting (especially the males) and if they feel your fear they will attack you anyway. You need to stand your ground this is true, but you must also be prepared to kill the thing if it goes for you. The animal will sense the fight in you and should leave you alone. If you stand there shaking, and the animal is hungry I believe it will attack you anyway.