At least for developers freelancing i dont think even marketing is all that hard. With the number of recruiters and such around its actually quite easy to get calls out and start working within a few weeks. I started out with old co-workers and such but found that the easiest way is to post your resume on one of the career sites (monster, indeed, linkedin, etc..) and you will get a flood of calls. 99% of them will be crap...but if your a 1 man show all you need is 1.