These days writers are told that in order to sell books we have to market ourselves online. We have to get our book out there under as many noses as possible to find buyers. Push it, push it, sell it!
But here's the thing. There's a reason "hard" salespeople have a rep for being a bit skeezy and slimy. People don't like to be sold to. I don't like to be sold to. And nothing makes me more sad than to see a writer I enjoy as a person, disappear into a mountain of self-publicity posts and tweets on various social networks.
I can only speak for myself, but as far as social networks go, it's you being you that sells me your book. It's you showing me that you can make me laugh, think, and relate to your words. It's not splashing your book title as far and wide as possible. Giveaways, sweet talk, swag, and news from the rooftops is great in small-doses, but don't disappear.
You being you, the interesting, funny, real you, is the best sales strategy I know of.