Beer Money

Well, I'd just quickly sign up for a business license with a name at your local govt...should cost you between $40-70.
This allows you to legally bring in income, although there is much under-the-table work too. (make sure you put about 20% for taxes)
If it turns into something substantial, remember to include the Fed. (but local is more important initially)

You can even advertise and setup your own site.

Do whatever you have a "knack" at or have knowledge of...accounting, clerking, medical, IT, tutoring, etc...and so on.
You can advertise, even setup your own site.
Only hard part, is everyone "wants" the service, but getting them to lay down money and pay you, that's the tricky part. (get some up-front BTW)
The littlest old lady will come up with ways not to pay. ("I can't afford it", "you didn't do good enough"...and so many more reasons and rationalizations)
And getting it consistent is even more fun.

You can try online "work" sites, but they are flaky...be wary of being hustled.

If you can get task/project with a business or corporate entity, then that's cool.
They pay bigger, more consistent...and it gives you the quals and rep to get more like it.

Since you're in the field you are, with the connections you have.
You may try grant filing and mgmt.
There are many profs and otherwise that just aren't good at that...or don't have the time...but still want the gig.
Research may be something, but I don't know what's the time investment on that.

Hope you find your niche.

 

I do some of those occasionally. I've usually used the credit to pad airline or hotel rewards.