Wrapping the rope around your foot may make you feel more secure, but interferes with the rhythm of footlocking. A good, easy-on-the-shoulders footlock is done smoothly and rhythmically, like rowing. It's fast and easy when mastered, a very efficient way to enter a tree (when tree is fairly open and rope is easy to get parallel, that is).
And much safer than it was when I learned. Hate to sound like some crotchety old timer, but....back in the day, we would go up unprotected, with no friction saver to hold the ropes together at the top. On large limbs this was very hazardous. Still is today, even with a prussik, which can loosen (and therefore slide all the way down) when pushed too far up near the limb holding the doubled rope. So be careful! Set a friction saver from the ground, or use two ascenders.