If you use him alot, he like you more. If he dies alot and you neglect him, he barely ever does any decent moves. Basicly the more money you pay the better moves he will do. If he has an overdrive you have a better chance of him doing a better move for less money. You should also raise his luck. However, there is not guarantee that he will ever do a specific move if you give him a certain amount of money. It just changes the chance of it happening.
Lets live together, I don't know how long it will last, but it doesn't have to be for show, together, till death do us part. - Kenshin "Shinta" Himura - Rurouni Kenshin