dktigert

I agree with all the previous suggestions.
Making a picture routine for how to go
Having a time schedule to go (hourly at least in the beginning)
Reward performing the routine (not necesarily the go)
Get really excited about the go
Stay positive

Make a big deal of big boy/girl panties with their favorite characters on them. Remind them when they finally get the hang of the potty they will get to wear them.
Use plain white underwear otherwise. Put the plain underwear between skin and pull up. This allows them to feel wet but keeps your floors/furniture dry.

Hope this helps. Good luck.