I ran a solo branding and web, product, etc. design shop, prematurely took it full-time and bet my livelihood on it, and effectively dead-ended my career.
The small number of clients I got were—according to them—happy with my work, but the only word-of-mouth inquiry that ever came in was a coke-addled soi-disant "tech visionary" with little money and no plan. Everything else came through exhaustive outreach and prospecting. After a couple years, the whole feast-or-famine freelancer thing went full-famine and sent me running back toward full-time/in-house work with my tail between my legs and—evidently—a stink of desperation that took a couple more years to dissipate enough for me to actually find a job. A job that paid significantly less, had worse benefits, and put me in a much lower, less respected position in a much less interesting company, doing much less interesting (and much harder) work than the one I left years earlier. An objective professional regress from which I've yet to recover.
If I've learned a lesson it's that there must be reasons I'm unable to find good work that are too close to me for me to identify myself, and therefor frequent and informative feedback should be sought in high priority.
I saw a number of my peers take the same leap I did and find enormous and continuing success despite having less experience and, in some cases, what I felt was much lesser work to show. Of course their success has since enabled them to eclipse me, as my development has been retarded by several years of bad or no work now.
I want to move toward self-employment again, but have virtually no professional network after so much failure (again, despite all of my few customers verbalizing that they enjoyed working with me and were happy with what I did for them), and have no reason to believe I'd have greater luck in another venture.
I'm commenting to share my story, but am really here to read about what others have learned that I might be overlooking.