I try to tell everyone about the book Toilet Training in Less Than a Day. It's kind of a pain to read (it's by the researchers who developed the plan), but the last part of the book describes a mother actually doing the training, so if you followed all the steps that she does, then it would be just as good. Since he's practically trained already, it would be pretty easy. In trying to remember from the book (which is available on amazon.com, new or used - which worked well on my 2-year-old) you remove all distractions (the family, just for an hour or two, maybe on a Saturday morning) and gather together his favorite snacks, treats and drinks, along with a doll that pees, and loose fitting training pants/underwear. Teach him the difference between wet and dry. Teach him to wipe and wash his hands. Have him "teach" the doll how to use the potty (and wipe and wash hands). Cause the doll to have an accident (when he's not looking), and scold her accordingly, and let him do the same ("no, Dolly, you are supposed to go in the potty..."). Give him 8 ounces per hour of his favorite drinks like orange soda or koolaid or whatever he likes (it's just for this session, so it won't hurt him). Give him a treat when he uses the potty (which he will need to frequently when he's drinking that much). Salty treats are good to get him thirsty, and keep pushing the drinks. Teach him how to get his pants (loose fitting!) up and down with two hands, and how to get up on the toilet himself (with a stool if he needs) or how to use a potty seat. They are perfectly able to do this, just teach them how, and have him teach the doll so she pees in the potty. Then check his pants every few minutes to start to see if they are dry, and reward with treats and more drinks. Have him feel his pants to see if they are dry. Tell him how proud his favorite characters will be (big bird, spiderman, the mail man, grandma, etc. - and maybe even have spiderman call to tell him how proud he is of him). Refer to those people/characters occasionally throughout the training. When he has an accident (it's best to do the training in the kitchen or somewhere not on carpet), be horrified and let him know that's not ok. Then take him by the hand from where the accident happened and run to the potty! Tell him when he needs to go he must run fast so he doesn't have an accident. Run back and forth to the potty 10 times from that location, and then every time he has an accident do the same thing (10 times), then have HIM clean up the mess! Have him remove the wet pants and give him paper towels or whatever to clean the floor. This is important and puts the responsibility on him. Continue checking his pants for dryness, and start rewarding him (a gummy bear, or chip or pretzel or whatever he likes, and drinks) for having dry pants (instead of for going to the potty).
Pooing in the potty followed the urine training naturally for my son. He's been potty trained for 3 months now, and does it all himself (he is now 30 months).
I may have forgotten some steps, so I recommend the book. It worked, and I believe it is the same system Dr Phil uses. Good luck!