First of all, you've gotta make your character as 1-dimensional as possible. There can be no depth to his/her character, no redeemable qualities, and no motivation behind his/her actions.

Second of all, your character's gotta look like a KISS reject. Wear lots and lots of black, and plenty of makeup on your face.

Use a red lightsaber, and only a red lightsaber. We can't go against Lucas' trite vision, now, can we, even when it would make sense to do so?

Finally, your character's gotta have Darth in his/her name, followed by something inspired by a "bad" word. For example, Darth Sipid or Darth Ane.