Become involved with the comedy community. There's a lot of up and coming comedians out there. There are podcasts, there are forums, there are big-name comedians who interact with smaller names on Twitter and so on regularly.
Create a lot of content. Almost always, particularly when you're entering a new field, creating a lot of content trumps trying to create perfect content.
Be topical. Very, very topical. If you post something moderately amusing about something that a lot of people are thinking about, you're more or less guaranteed to spread virally, at least a bit. The earlier you move on a subject, the better.
Have an opinion. From my observation, even more than most content-driven industries, comedy and satire thrive on people with strong opinions: from Marcus Brigstocke to Margaret Cho. Often, people will share your content as much because they agree with your point of view as because they think it's funny.
Do spend a lot of time self-promoting on Twitter, Facebook, Reddit, and whatever other social platform works for you. Find one that works, and push your presence there for all it's worth. Don't try to do all of them at once.
Stick to it. This isn't a "done in a month"-type project. You'll need to persist for a year at least, I'd guess, to get some decent traction.
I could continue (at some length - this is kind of What I Do), but I've got to get back to work :) Hope that helps!