While I am not outright endorsing any specific candidate right now (still painted unconvinced), I am a bit of a fan of this site which helps you register to vote, see if you are already registered, and helps you w/ a variety of other questions about being registered to vote.
Unless you are military and needing to vote absentee, from overseas or otherwise, you will need a site similar to this.
Now go get registered. I still don’t know what I am going to do w/ it, but I have taken the first step.
(I finally changed that pesky party affiliation detail.)