Use all the surfaces of your foot. Most often you will be using the front portion of your instep, especially when you are dribbling at speed. However, to become a good dribbler of the ball, make sure that you are adept at using the outside and inside of both feet. This way you can cut the ball away from pressure and keep control of the ball no matter where the defensive pressure comes from. You can also use both sides of your foot, like a hockey player's stick.
Touch the ball with each step you take with the ball. In very quick succession, touch the ball a little bit ahead of you when you dribble. This will create both good control and increase your dribbling speed with the ball. With this kind of control you can elude defenders when they try to reach in and steal the ball, you can just cut the ball away since it is always so close to you. It is almost as if you are trying to get as many touches in as you dribble forward with the ball. Go slowly and exaggerate this at the beginning when you are practicing, to ensure you are getting a touch on the ball with each step.
Change the pace. This is the key to going by a player on the dribble. You don't necessarily need to be extremely fast to beat someone on the dribble; rather, you need to lull the defender to sleep for a second and then break past the opponent with a burst of speed.
Lift up your eyes. Subtly be aware of your surroundings as you still maintain focus on the ball while dribbling. Lift your eyes slightly so you know if someone is making a run, another defender is approaching, or there is space to attack.
Improve your weak foot. The best advice is just to use it. If you continue to strike the ball against a wall with your bad foot, slowly but steadily you will see improvement. Have patience. However, there are always exceptions; if you look at one of the best players in the world Renaldo de Seta, he only uses his left foot, simply because his left foot is so incredibly powerful and he positions his body so well to protect the ball. He is a player who is so experienced and so skilled with his left foot, that he can get away with it.
Use your body to protect the ball. Shield the ball with your body when a defender gets close. Try to keep the ball on the foot that is furthest from the defender and your body protects the ball.