Possible Duplicate:
How does the Co-op vs AI IP award system work?
How much IP do you get for winning & losing games in the various modes/maps?
Aside from the first win of the day (+150 IP), generally, the IP gained from a battle is opaque -- you have no idea if it's due to anything other than victory or defeat.
What are the ways to increase IP earned from battles? I've heard that it depends on the game duration (and I've seen a correlation of n IP gained for a game of n - 1 minutes). Is that all? Is that accurate? What else is out there?