L.V.
What worked for my son was we started a "sticker system". I took him to the store with me and let him pick out what stickers he wanted to put on his chart and then told him that everytime he went to the bathroom we put up a sticker. And if he had so many stickers in a day then we either went out for ice cream, or I bought lots of small cheap toys and stuck them in a little rubbermaid container and he got to pick one toy out of that. Once he saw what was all in that box, he worked extra hard to earn more stickers to get another one. It also worked well when I had to teach him to sleep in his own bed. By the time we ran out of stuff he was use to going to the bathroom. However, I did have problems with him going poo poo in the potty. For some reason I've heard it takes boys longer to do that then pee. My nephew didn't start pooping in the toilet until he was 4 years old. He'd hold it in until his stomach was hurting and then once we placed a pamper or pull up on him, he was relieving himself. But maybe some of these ideas will help. Just do activities you know he'll enjoy doing and want to "work" for.