L.-
i have a son who will be 3 in September and I take care of a boy who will be 3 this month. My son was potty trained very fast, he was very ready but I am still working on it with the other one, lol! I really love the bjorn potty chair and bjorn makes a seat for the big potty,. This one is perfect for boys because it has a lip that prevents messing on the floor.
I can tell you a timer works great for having them "try", they would sometimes get upset at me for having them go but when I made it a game with the timer they would stop what they were doing and run. I provided plenty of drinks- and treats work great. m&ms, sprinkles, fruit snack etc. when they are successful.
With my son I will tell you when we were just practicing, I used pull ups ( telling him they were big boy pants and they would leak...out, but at home let him go around the house naked.
Once I got serious and knew he could do it- I completely removed diapers and put him in underwear. I am a strong believer that going back & forth, even with pullups, is confusing. We now only use a diaper at night immediately before or after he falls asleep.
My son sat down at first but once he learned how fun it was to stand up he would rather do that. The other boy I am working with has mixed feelings on standing up so it just depends what he feels comfortable with- Easier at public toilets when they stand. :)
I hope I helped and good luck!