Two things control what you get offered: where you'll travel and when you're free.
Your base county, nearest town and travel radius decide which venues you appear for. A radius that's too small keeps you out of searches; one that's wildly too big gets you offers you'll decline. Be honest: it's more useful than being optimistic.
Availability lets you mark days or parts of days you can't work. Setting it properly means fewer offers you have to turn down, and agencies quickly learn to trust the acts whose availability is real.
Being booked already counts automatically: you won't be offered a gig that clashes with one you've accepted.