Sweeps should always be followed by another technique which takes advantage of the opponent's loss of balance. Sweeps are often done when the opponent is moving, just when the body weight is being transferred to the foot which is swept.
It is more common to sweep the opponent's front leg from the outside. It is possible to sweep the front leg from the inside, but this increases the probability of a counter attack because it starts the opponent's hips rotating forward. A successful sweep from the outside turns opponent's hips and torso the other direction, turning his back toward the sweeper.
To sweep the opponent's rear leg, it is best if he/she is in a high stance with weight on the rear leg. To sweep him it is necessary to get close enough to jam his front leg and hand, preventing any counterattack. As the sweep is applied, the opponent's upper body should be pulled in the opposite direction of the sweeping foot.