I've been a consultant and entrepreneur for over 15yrs, and it's still hard
to find "side gigs" that leave enough time for the startup or enough money
to help. Beware of what you're getting into.
I agree with William... go to meetups. Here in Austin we have a reasonably
sized R group, but our group is pretty knowledgeable and there aren't many
leads... mostly people looking for work. Go to web meetups, data
visualization meetups, and other startup events. Also consider any kind of
business analytics meetups where there are folks who may need more advanced
work than what they can do in Excel. Remember that your consulting services
are best received by people who don't already have knowledge in your
subject matter expertise.
Finally, most of the smaller side gigs I've
landed lately start with requests I respond to on Twitter. I've also
partnered up with small local tech/consulting shops in town who need a
quick hired gun here and there.
Bottom line is side gigs are hard to come by and are a completely different
line of business. Finding them requires time. Clients pay late, require
proposals, require insurance, require legal contracts, work orders, and
often like to "hurry up and wait".
One of my early ventures was a DW/BI
consulting practice, so over time I amassed a lot of the soft
infrastructure and IP to do this quickly... but just because it's side work
doesn't make it any less of a business. If you don't do it right, there's
also a risk to your new startup. Make sure you cannot be classified as an
employee and that you're keeping any IP you develop separate from your
future business. In some states, this means having more than one gig to
show you're not dependent on a client for a living.
Best of luck!!