Go to the clubs your interested in playing in, talk to the right guy, be nice, smile and if he likes you which you must make sure he does, then chances are he will give you the opportunity to play his club.
If he still says no, then offer to play the first gig for free.
Also tell him that you keep hearing how cool his club is, he will like that. But don't make it sound too smarmy (cocky or slimy).
Good luck
Dene (london UK)