As a guy who does almost exclusively freelance/for-hire work, my best suggestion is to really find out who you're going to be playing with ..... are they kinda crappy bad players looking for a root-five-root thing, or actual established pro-level musicians? Once you know that, are you comfortable with the style of music? Is your sight reading up to speed?
I get a lot of truely horrible requests that I turn down flat. I guess it helps that I don't
need the cash to pay the bills, so I can afford to be fussy.
Just a suggestion, but if you don't desperately need the cash, try to avoid the bad-band dates. Those bands can quickly spread a negative rep about you that will ultimately cost you other jobs, possibly other jobs with good groups paying nice money.
Also, it's just a quirk with me, but once I take a date I don't back off of it just because a better paying gig comes up. I've managed to keep a pretty good reputation going over the past 5-6 years of free-lancing by being very up front with people .......
