Who's your audience?
Answer that, and you'll know where to focus your efforts. Wherever that audience gathers; whatever the norms are among them; whoever within that group makes book recommendations people pay attention to.
Blogging and telling friends is nice. It also doesn't get you very far, because thousands of other eBook self-pubbers are doing precisely the same thing. The common reader is inundated with plugs for self-published work; as long as they're promotional plugs, most readers will ignore them simply because he comes across so many. Two exceptions to this:
- Some works may have some special feature that'll grab some eyes even in a plug ("Ooooh, I love vampire time travel stories!" or "Hey, a how-to book on building origami tables - I never thought about it, but that could be cool!" or even "Cool, this book only costs a buck!").
- If your book is good enough and you get it out to a large number of people, you might be able to get a word-of-mouth thing going, and then you're golden - you've got people recommending your work to friends; that's just about the best publicity there is. But, this is hardly something to rely upon; it depends heavily on the quality and accessibility of the book (which is practically orthogonal to marketing strategy...); and it's pretty much outside your own control.
So, knowing your audience and targeting them is extremely helpful - it helps you aim for the first, "special feature," reaction, and it focuses on groups most likely to have that reaction.
A great difficulty is that many ebooks (and short story anthologies even more acutely than novels) don't really have a clear audience beyond "readers" or maybe "readers within [Genre X]." And that's tough, because so many readers are spread out all over the place and it's hard to find a clear focus, and because such a broadly-defined group already has plenty of reading material to their tastes, and is already fending off similar broad plugs.
So what I'd suggest is to see if you can brand yourself. Figure out, in detail, what existing communities would most enjoy your work. Build around that. If you need to change, add, subtract - I'd strongly suggest doing that. Build up your brand, know who you're aiming for, figure out how to reach them. Each of those steps will be very individual to your particular work and style - but those are the steps worth figuring out, and taking.