There are hundreds of uses for a lightsaber in the household alone -- and only a few of them involve dismembering kitchen droids -- but most lightsaber techniques boil down to four key actions.
Slicing: From tauntaun bellies to Tofurky roast dinners, lightsabers excel at slicing clean through stuff. Experiment with different angles and speeds for maximum effect, but remain mindful of your surroundings. An offhand lightsaber swing can cut through reinforced beams, plumbing, electrical wiring or grandmothers.
Stabbing: A lunging stab or a sneaky activation of your lightsaber next to an adversary's chest is a great way to end a saber duel -- at least in the movies. In everyday life, however, it's a great way to begin carving a large space mammal or to steadily build up heat in a larger mass. This leads us to our next action.
Melting: Yes, as made evident by your many cauterized nicks and scratches, the blade of a lightsaber gives off a lot of heat. Run it through a large cut of beef and you'll quickly notice the pleasant aroma of cooking steak. Alternately, this is a handy way to destroy things that can't otherwise be sliced -- such as a blast door on a starship. Just activate your lightsaber, stick it in and watch the hot dripping begin. Who needs keys? You'll be through in no time.
Deflecting: Should some prankster try to slice you with a lightsaber, remember that you can deflect his or her attack with your own lightsaber blade. This trick also works on bolts of energy fired from a blaster pistol or rifle. In most cases, you'll want to deflect the bolts back at the person who fired them at you in the first place, but with enough practice, you can also redirect them just about anywhere. Either way, it helps if you have a strong affinity for the Force, as this will enable you to anticipate the exact trajectory of the incoming bolt.
Force usage can also enable fancy saber throws and boomerang retrievals, but these techniques should only be attempted in duels or to impress girls.