Any potty-training ideas??

Anyone have any great potty-training ideas? My Mr. Clay is being a bit stubborn. He is almost 3-1/2, and has been going to the bathroom in the potty since he was around 2-1/2, but he isn't consistent. Some days he goes really well, other days he runs away from the bathroom, screaming "I DON'T WANT TO GO POTTY!!" I've tried not to put too much pressure on him, while still encouraging him, and tried bribery with treats, but want to get rid of diapers once and for all. Any ideas?