For the most part, I try to improve articles on microbiology and molecular biology, my two academic loves. Anything large enough to see with your eyes is probably too big for me to understand. In general, our microbiology/molecular biology articles are in a sorry state, and would require many lifetimes to bring up to snuff. If you've got the time to help but don't know where to start, let me know and we can coordinate our efforts. Similarly, if there's some way I can help with whatever you're doing, please let me know.
The unwelcome intrusion of real life sometimes keeps me from my more important work here. If you need to reach me for whatever reason, dropping me an email is a more surefire way to catch my attention. If I don't respond to your email, I'm probably briefly off the grid. Be glad for me.
I also write a monthly newsletter for WikiProject Medicine. You can find past issues here, and subscribe to the newsletter (it's free!) here.
Even considering the lousy pay and poor staffing, I've found editing here to be fairly enriching. I hope you decide to stick around and help out. If you do, I hope to see you out there. Happy editing!
In the interest of transparency, I'll try to list the reviews I've undertaken here. Others have done the hard work. If the articles are good, blame the nominators, et al. If they're lousy, shame on me.