I've been self publishing for about a month now. The process is fairly straightforward. Register on the publishing site, submit your book, and let the monkeys in their servers make it available for publication.
There's obviously a boatload of other books from other authors out there being published at the same time so without letting potential readers know about your work, you're not going to get much in the way of sales. My sales have been best at Amazon and Smashwords. Kobo thus far has seen a single sale and I've yet to make a sale at B&N. (mind you, I don't know anyone with a Nook so this isn't a huge surprise). Other authors have advised that you don't truly start to make sales until you've got 20 - 30 ebooks out there. I believe that. For what I have made so far, I can take my family to McDonald's.
Advertising. It's vital. I use social media a fair bit and could always use more. My primary means of advertising are on my blog (mudak326.tumblr.com), Twitter (@JoeMudak), and Facebook (Joe Mudak). Secondary are FetLife and various forums where I've mentioned my stuff. This includes (now) here at FSTDT. And, of course, at the end of each ebook, I include links to all my other ebooks for purchase. So if you like, say, my ghost story, Voices Trapped in Yearning, you know how to get my crime drama, Assets Under Management. The links are tailored to each publishing site. The first ebook took longer to get going on each site than its successors and it's not a complicated process any more. I've reached the stage where it takes longer to photoshop the cover than it does to submit the book for publication.
I'm not really in a position to judge how effective my advertising has been since I don't see a direct cause-effect relationship between my mentioning the books on any site, and their sales. I realize that I started this thread less than 8 hours ago, but I haven't made any new sales yet in that time.
Hope this helps!