sorry man. we're not even sure if HJ is gonna let anyone from this site beta test in the first place. I know. I would consider myself the most hyperactive wannabe beta tester here. I feel your pain.
The easiest way to help you be selected for beta is to be an active part of the HJ community by posting. When you contribute good helpfull ideas the gms/staff look at that and select some people from that.
Also there will be contests in the future giving beta slots away so keep checking the site and we'll give you up to date news when that occurs.