My wife was determined not to have to clean and maintain a potty for our two, so we avoided it entirely by using a set of foldaway steps that sits on the toilet rim. I don't know what the etiquette is for posting product links but a search for "toilet steps" will show you what I'm talking about. Highly recommend.
The power of example cannot be denied. A friend of mine once has his son walk in on him on the toilet, so he showed the boy how he does it. From that point on there were no issues.