Need to take on freelancing - but what?

I have a startup with a product in the market which is doing OK, but not great (yet). We are two people and have revenue which allows us to pay minimum salary to survive. We'd like to take on some extra freelancing work, to generate extra cash. However, we have no clue what the market is like in the bay area. We don't want to take work that would make it impossible to keep running the startup. I guess that means we can't take work on site, and would be best off with projects where we can deliver work each week and get paid for it, rather than having to be there between specific hours and keep timesheets? We can both code but feel we've gained a lot of experience beyond coding the past years and would like to put that experience to work, rather than just grinding code all day. I'd love to hear from other people here on HN what they've done in a situation like ours, and if it worked out or not, and why.