Remember to keep your heels down and wrap your legs around your horse like a beach ball, this will help you stay balanced and controlled! :)
Riding without stirrups is all about balance, make sure you are well balanced and that you share a common skin with your horse with a following and independent seat. Start at the walk first and progress to other gaits as you get better.
Take your stirrups all the way off so you don't have the option to put your feet back in them!