Get a web page of some description - photos, blurb, sounds, images, etc.

Get your material recorded - put it on Soundcloud or similar.

Get a demo CD/DVD done.

Get yourself filmed - put it on YouTube or similar.

Get some print flyers with all your info on them.

Get round the clubs and do a floor spot - take in the style and audience of the club - if you think you might be Ok there, leave your promo stuff with them.

Eventually, and it might take time - if you're any good - you'll get a booking.

Be patient, and be organised without being over-pushy.

And don't be put off by the cynics who say you need to be one of a 'family' or some 'in-crowd'. I know several club owners who are willing to take a punt on a new face - some small clubs can't afford huge name acts and may give a relative unknown a trial. But you have to be able to put over what you do. So make sure your act is as good as you can make it.