C.M.
I struggled the most with potty training my youngest son.
what finally worked for us was kinda different... my son loved blowing out candles. I kept a candle on the back of the toilet and while he sat there I would hold the candle, light it and he would want to blow it out so badly, he'd go potty so I would allow him to do so.
Now this trick may or may not work for you, but look for something he really, really likes and try to use it as incentive no matter what it may be!
Good luck!