I've heard many people use sticker charts and small incentives. My son likes to put squares of TP in the potty after he goes. We've gotten #1 but we're still working on #2. Maybe find something he likes for encouragement.

Absolutely...
Lots of liquids.
Let them have something that makes them laugh.
Make it a part of the daily routine, a specific time(s).
At first you want to discover what their pattern is by taking them every hour regardless if they have to or not. Once you have the time-frames that they need to go, stay with that.
For B.M.s, have them try before their bath/shower and then they can go from something stressful to them to something more enjoyable.