I have a parenting trick that has worked wonders over the last months. It's called, "this one or this one?"
It started when he was insisting on wearing the same striped shirt all the time, no matter how dirty. So after weeks of torture getting him dressed in the morning, one day I held up two shirts and said, "do you want to wear this one or this one?"
"Ummm," he replied. "This one!" And he picked one and wore it. This turned out to be no fluke. It worked again and again. Joe nearly wept with joy, since it is he who dresses Theo in the morning most of the time.
It works with potty training. He normally wants to wear pullups, not underwear. But if I hold up two underwears, he has to pick one of those, and he is satisfied.
And it extends beyond clothing. It works with food and drinks. It works with which bedtime story we're going to read. It works with which toy he'll get at bathtime. It works with which teddy bear he'll sleep with. You simply give him a choice and he always does the "ummmmmmm" which just kills me, it's so adorable, and then he chooses.
Although I have to admit, my trick backfired on me the other day. I was sitting here at the computer, working, and he came in with two shirts. He performed our whole routine entirely on his own.
He held up the shirts and said. "This one or this one? This one. OK!" (I often say OK after he chooses.)
Then he put on one shirt and put the other back in his drawer. Fine, right? Except he continued to do this for the next half hour. He kept bringing two shirts, having the conversation without me, and changing shirts. At the end shirts were all over the floor.