Keep ahold of both brakes. Don't let go until both feet are on the same side of the bike. Then the wheel won't go anyplace you don't let it.

As you slow to a stop, remember to turn your bars AWAY from the foot you intend to put down. (If you unclip left, e.g., turn your bars to the right.)

Choose which foot you prefer to put down first, and make a habit of that so you don't have to think about which foot it's going to be each time. It's good to be able to unclip either side, in case of poor footing or emergency stops, but that's something you can practice after you're confident unclipping with one foot.

Practice standing on the pedals when you aren't stopping. Get used to how your balance feels standing. Stopping and starting is just standing on the pedals for a moment.