Running a giveaway is a good way to publicize.

People like free, and like to win things.

It's nice if you can find another author in your same genre and run a joint giveaway - double the prizes, double the creativity, double the reach as you share.
Besides all the things mentioned (FB, G+, Twitter, Blogs, Goodreads) another good thing is to upload pictures of your book on Pinterest, with a link to where to buy it. You can ask writer friends to add it to their "book" boards, and then anyone following them will see it.
Running an author page on FB can be helpful. (I don't have one, but I've seen it be a good thing for others.)
If you have an ebook, running a free promotion can generate interest. (I've given away 165 copies of my book in the last 4 days, during the giveaway I'm hosting.)
Giving a copy to your church library, and mentioning to people that it's there, has been helpful for me. I'm also planning to give a couple copies to a nearby church's library - I discussed things with the librarian, and she's excited to let people know they're there, and where to get them.
Having a "for loaning" copy is nice. I write instructions in the front, ask people to sign it in the back, and "give it away" at Bible study, or something - eventually I get it back. Usually I write a date in the instructions in which I want it returned to me.
If you find blogs/FB pages that promote writers, and do reviews, it's good to see about working with them to get a review or a slot to guest post. Some people want a free book in exchange, but I think it's worth it.
That's about all the ideas I've got, yet, haha.

I'd love to hear any more ideas y'all have!
~ZA