Here are some tips on how to find a co-maintainer:
- Post an announcement on the project page itself that you are looking for a co-maintainer
- Post to the Development mailing list
- Post to the co-maintainers group and, if your request is for people with a specific skillset then cross-post it to an appropriate group
- Find people who consistently post issues or patches in the queue and use their contact tab or discuss the idea in the queue.
- Find a module which has the kinds of features you need (e.g. AJAX features) and then offer to provide review/code to that maintainer if they will help you with your module
- If you just need reviewers, post to the reviewers group