You need to learn to move yourself with your mind. In my opinion the best way to learn how to do that is to practice with telekinesis. Once you get the feel of moving other objects around, it's then nothing to do the same thing to yourself. You will end up having awesome control that way. After a while it will become so natural to fly that you will be able to do it without hardly giving it a thought.

Also, anytime you find yourself looking down from a high place, be sure to jump! Just make sure you know it's a dream first of course.