First you can go to Rock the Vote, a music industry public awareness promotion, has set up a WWW page at http://www.rockthevote.org/ which will lead you to an on-line voter registration form.
There's one form custom designed for each state.
You fill it out on-line and click on "send."
The completed form will be mailed to you in a few weeks. Check it, sign it and mail it in the postage paid envelope.
It uses the national voter registration form, which state offices code for Office of Hawaiian Affairs voter registration. So if you are using the Rock the Vote registration, pay attention to the portion regarding ethnic background.
Also the state's new Office of Elections, headed by Dwayne Yoshina, has stocked its cyberspace location, http://kumu.icsd.hawaii.gov/elections/, with as many voter registration forms as you need.
Here you will find a special voter registration form to download. After you print it, fill it out and sign it, you mail it back to the city or county clerk and you are registered to vote in the Sept. 21 primary election.
All that without visiting any bureaucrats. Wait a few days, however, before trying the state form, they are still adjusting it and all portions may not work.
That's all there is to it. Just don't forget to vote.