Lots of good advice here. I'll tell you what I agree with and what worked for ME/us.
I'm basically lazy and didn't want to do the whole clean up thing before he (boy 34 mos)was ready. Then I read a child-centered book called, "toilet training". It suggested getting the doo-doo part of the job taken care of FIRST.
I would stop all efforts for a little while and make it a non-issue for a while. Then see if, while wearing pull-ups, you can get one successful urinating episode a day. (ours was just before bath while the water was running... sometimes I even poured warm water over him while on the potty). Lots of praise, make it fun. And talk about when he uses undies he'll be clean all the time - that'll be so wonderful FOR HIM!
Then, when my guy started a regular bowel movement TIME, I anticipated. I had to fight him to change his poopy diaper, so sometimes I waited until it started to sting. And, I set up a bribe: get doo-doo in the potty and go shopping for his toy he's been wanting. (you know all those times you say, 'NO' to something he wants, make a deal with him. This does not continue for long but gets him motivated). Be sad for him, (not to get it this time) be excited for the possiblity with him. This took about two weeks after his first success to get it regular, and the 'gift' got smaller and smaller.
Then, we turned to urinating more frequently for stamps/skittle/stickers, and finally, daddy picked a weekend and they did it all together; drinking and wee-ing standing up at the toilet.
This is about him learning about his body signals, and getting attention good and bad for this personal body function. And, it's kind of a right of passage... does he want to grow up or stay your baby for attention?
Love him through it!
I hope some of this has given you an idea you can use.
Good luck.