I read a useful article on Gizmode on li-ion batteries. Thought Id share it with you. Here are the tips (sounds simple, but I dont comply with them!) See link for full article.

Do not let it run out completely all the time. Full discharge puts a lot of strain on the battery
Do not keep a Li-ion battery fully charged all the time, either. If you don't use your battery it might suffer from capacity loss
Keep your battery in cooler temperatures. Hot hot heat is not good for it
If you're gonna store your battery, leave 40%-50% charge in and store it in a cool place (i.e. fridge).



Link: Gizmodo, the Gadget Guide