www.aviationjobsearch.com that's a start, seems like there's loads out there right now
You're not the only one who has been on pprune looking for a foot in the door, most freelancers have done hard slog on commercial for years and just slogged a bit further.
From what you just said you've done GA, corporate and single crew operation, so what else do you need to know? Freelancing is a funny game, doesn't matter how much you love it because it all boils down to supply and demand.
If you've also been to interviews then keep at it girl