Really I don't know why people think it is such a big deal. My only tip is to consciously think about your foot being clipped in when you come up to a stop. That way you're ready to unclip. Unclip way early coming up to a stop. You don't need to lift your foot out, just unclip and rest it there and you can clip right back in.

After awhile your muscle memory will kick in. When I come up to a 4 way stop I don't unclip at all unless I need to stop and wait. I can come to nearly a complete stop (Not quite able to do a track stand) and not unclip. If I do have to put a foot down the twist is part of my natural reaction now. It is no more unnatural than putting your foot down from platform pedals.

I don't think you really need to "practice" unclipping per-say. Just be thinking about it as you ride, until it becomes natural.

Also I always unclip my left foot. If I unclip my right foot my right leg gets all full of grease because it rubs against the chain if I'm not careful. If I'm coming to a complete stop I often don't tilt to the left. I'll kinda "step down" off the saddle and straddle the top tube. I do this if I've come up to a light that just changed red and know I'm going to be there for a couple minutes. Easier than wobbling over onto your tip toes.

That's my limited advice.