We did the Potty Party with our first, too. Potty training in one day ... yep, too good to be true, unless your child is not strong willed and is definitely ready for it. It was a total disaster with our son. To this day, we still laugh about how ridiculous we were as first-time parents doing the Potty Party.
If it was the same disaster we had, your son isn't ready. We waited a couple more months before trying again. Honestly, what turned things around was when all of our son's friends from daycare moved to the preschool room and he was left with the little kids. We then moved him to underwear and made major progress when he was a few months past three years old.
Second child, we took the lead from her. She wanted to use the potty at 2 1/2 and we went from there. She trained within months. No silly dolls, timers or parties in the bathroom, just put her in panties and took her when she needed to go.
Good luck!