Since you're already advertising in your signature, there are two things you can do:
1. Offer to review people in chat and direct them to your thread.
2. Go out and review lots. It's not as obvious now, with how it isn't as easy to for people to see they've gotten a review, but the more you review, the more people see that you're a good reviewer and will want to ask for your reviews.
Once Notifications are up an running though, and if you've been reviewing, the requests should come rolling in. ;P
