Since the forehand is generally more powerful than the backhand, as well as better for smashing high balls, it is often important to be able to use the forehand out of the backhand corner. An inability to do weakens your game. Of course, some players are not fast enough to do this regularly, but even they should consider doing this against certain shots.
Stepping around the backhand involves five parts: (1) Setting up the shot, (2) assessing whether to step around or not, (3) the footwork itself, (4) the shot itself, and (5) return to ready position.
Getting a shot to step around on involves good shot selection on your part, ball placement, and quick judgment. Generally, there are four shots that you might step around the backhand to use the forehand against: pop-ups, pushes, blocks or weak drives, and deep serves. Pop-ups are the easiest as they allow the most time to move into position. Blocks and pushes are more difficult because you will have less time to react.
Generally don't move until your opponent is committed - the better the player, the longer you have to wait since a good player can fake or change his direction at the last moment.
You can anticipate most pushes going to the backhand as your opponent often doesn't want to give you a forehand shot by pushing that way. Of course, besides direction, you will have to judge the depth of the return or you might find yourself trying to loop a ball that lands short.
Unless your opponent is very predictable, you will have difficulty anticipating where his block or drive is going. You'll just have to wait for him to commit, and then, if he goes to your backhand, you'll have to quickly decide if you should step around for it. The important thing is to force a weak return that you can step around on (or perhaps not, if the return doesn't go to the backhand). There are many ways to do this, such as spin (especially heavy topspin), speed, quickness, ball placement, shot selection, varying the speed and spin of your shot, and, of course, tricky serves. Experiment and see how and where your shots are returned. For example, if you are in a backhand-to-backhand exchange and you suddenly hit a quick one to your opponent's middle (his playing elbow), you might force a weak return to the backhand that probably won't be too angled. Be ready to step around, but be careful - he may go down your forehand line at the last second and all you'll be able to do is applaud his fine play.
If you have a strong forehand (relative to your backhand) but rarely step around your backhand, you will not be taking full advantage of the natural strength and power of the forehand, therefore handicapping your game. Turn your forehand into an all-table weapon!