Yeah most places ask for a minimum of 20 mins, best thing to do in my opinion is make friends with some bands, you don't have to bum their stuff, but it can't be any old band. So for example my old band who would play grungey punk stuff use to support a Riot grrrl/new wave band, a grunge band, and some snotty posh punk band, and we shared fans, or stole them
Also when you're arranging/heading your own gigs, it's good ask other bands you know to support you, as they'll call on you if they need another band for a bill they're playing on. Your friends always make good crowd fillers, as they'll bring their mates for a drink too, venues only put up with you to rake in some booze or ticket money, and because your friends might be jumping about, and they'll encourage others to join in. Eventually, just before my band split, we were at the point where some venues would cut us some of the ticket money, and well that was great, because we could have a drink and get a taxi home instead of the bus haha You might wanna get chummy with some venue owners, I'm no star on photoshop but last year I made some flyers for a guy who puts some real nice punk gigs up, featuring the likes if UK Subs, Discharge, Vice Squad etc. if I ever asked for gig if I was in a band, he'd probably be happy to return a favour.
Connections, practise(cliche but so true), and get atleast something on the internet for people to hear, also be an add whore, but make sure you're adding your target audience, that's my advice anyway
