There are many ways, all with advantages and drawbacks, depending on how's the scene in your area.
Shortest path: get your own gigs together (brings a 1000 issues, is quite risky and you must be into it all the way to your soul, but is very rewarding if you cut it right and pays strongly in the long run. Your crowd can open doors to clubs and gigs if they love you. What friends are for anyway???)
Hardest path: sending demos to promoters (gotta rely on luck and sure to face fierce competition no matter how good you are. Promoters rarelly listen to these, unless you hand them personally and are close friends to them and beg for a shot on your demo at the way to work
- but in this case you'd get a spot straight away if you're any good anyway
)
Not to damp your enthusiasm but getting a spot in a club takes time and dedication, loads of dedication. There's no shortcut to it unless you're one-of-a-kind (and that comes with time and dedication too...) or you're friends to promoters, DJs and the ppl that floats around the scene.
Even then, unless you really bring some advantage to the other than your DJing (for instance sponsorships tot he club and the like), for the best it may be there's an estabilished "métier" already taking care of these stuff (DJing and the rest).
On the other hand, if you really want it and you're easy to get friends to ppl, are nice and dependable, has good will and has some good music and skills to back it all up, at some point you'll be able to prove and please the crowd. And that brings a lot of changes and you may end up there were you're dreaming now.
Very important: don't rush, don't despair, don't step into others and enjyo every second of this way to the club booth!
And sorry for the long post