How to jungle in a Summoner's Rift?

So I've been wanting to play jungle role for a while, and play champions like Lee Sin , Master Yi , Kayn , and Diana . Each time I try, it doesn't go too well... which items should I buy, what route should I take, and how can I successfully 1v1 the other jungler if I bump into them?

I've been buying life steal and attack damage items like the Bloodthirster and the Ravenous Hydra but they probably aren't the best items to use._.