A whisk gives you a bigger stroke than any other kind of beater, and therefore more volume.

Separate the eggs, putting the whites in a large, perfectly clean bowl .Begin beating the whites slowly, using a small range of motion to break up their viscosity.

Continue to beat steadily, using larger strokes, until the whites have lost their translucency and begin to foam. If you relax your shoulders and work from the wrist, the job will be much easier.

Now increase your speed and use an even larger range of motion, to incorporate as much air as possible. Continue to beat until the whites have mounted to the desired degree.

In most cases, the whites should be stiff but not dry. Test by lifting some of the whites out of the bowl; the peaks that form should be firm but glossy, with tips that droop gently.
To beat or more properly whip egg whites, the type of bowl you use is of greater importance than it is for whole eggs or egg yolks. Avoid plastic bowls, which, despite washing, can retain a grease film that will inhibit the "mounting." Unlined copper bowls are best for turning out stable, voluminous whites, due to a positive reaction that occurs between the whites and the metal. If beating whites in a glass or stainless steel bowl, you can help stabilize them by adding a pinch of cream of tartar. I think that whites are best beaten with a balloon whisk, which should be large enough to keep a maximum amount of white moving and aerated as you whip.

If you overbeat egg whites they will be stretched to capacity, so they can't expand farther in baking to leaven foods. Overbeaten whites are grainy and, because water leaches from them, they will slide around in the bowl if you tilt it. If you have overbeaten whites, they will have to be discarded.