Online form. Takes all of two minutes, if that. Seriously.
Print it, sign it, slap a stamp on it (and maybe a piece of tape) and you're good to go. You don't even need an envelope.
Do it right now, if you can. Many states have early October deadlines to register. That's just two weeks away.
If you're not sure whether or not you're registered, you're probably not. Register again.
I don't care whether we're voting for the same guy or not.
Just register and vote, k?
It ain't a right, it's a responsibility.