The key to my son's success was going from diapers right to BOXERS. I tried briefs but to him they felt like diapers and would pee in them. With the boxers I would take him every 40 minutes to the potty to go. In the beginning I also put cheerios in the toilet as a fun game for him to pee on the cheerios.
Also, DS stands up to go pee pee, which I think goes against the "recommended" way to potty train a boy. But it worked for us.
#2 was a different story. He hated to go #2 whether in his diaper or in the potty and would cry about it and hold his butt. So as soon as I saw that he was ready to push I would put him right on the potty. While he was on the potty (toilet) pooping I would read him books. I also started putting him on the toilet every night before bedtime even it he didn't have to go and read him books. Now he goes poo poo every night before bed. He has been potty trained since middle of August.
Oh and he was bowl trained before he was pee pee trained. So he was still wearing a diaper but doing poo poo in the toilet.
PS: I had to order the Boxers because I couldn't find any stores that sell boxers for 2 year olds. Amazon had them... "babys first boxers".
Re: DS Potty Trained at 2 1/2