Promo is something you can do on your own but having help definitely helps. Blogging is definitely an example. I could blog every day of the week in an ideal world. But I don’t live in that world.
There are a bunch of groups out there for promo. MurdermustAdvertise on yahoogroups is one that has been around for years. You can go there even if you are not a mystery writer and ask promo questions. The moderator will not let you promote to the group but fair is fair. That’s not the group’s purpose. But just about any question you want to ask on promotion can be and will be answered there.
Another group I like is Marketing for Romance Writers also a yahoo group. You can subscribe They have specific routes to help. You can guest on their blog, they have “talks” about promo, you can find places where you can blog tour or do a chat. It’s all there and again doesn’t seem to limit itself to just the romance genre.
Twitter and Facebook are great tools, but a friendly internet group can help you use them better.