Friend and befriend
Check out and "like" fan pages on Facebook, author profiles on Goodreads, and Amazon. The small task of "friending," "liking," "endorsing," or "following" helps indie authors and their books become visible.
It takes a village to promote a book
A book becomes a commercial success when people tell others about it. If you enjoy a book, tell friends. Use your own social media outlets to mention and link to the book or the author. Invite your book club to read an indie. (Lots of authors will visit book clubs to chat about their book either live or via Skype). Giving indie books as gifts is another way to share the love.
Help make connections
Authors will often have giveaway download periods on Amazon and other sites. If you want to go the extra mile, download the freebie even if you have it already. If you are in the market for another book of a similar genre purchase that one at the same time. This couples the indie book with the established book. The two books become linked and automatically promoted by the engines that do such things on that site. Tell your friends to do the same!
Offer endorsements or reviews
Write an honest, positive review on Amazon, Goodreads, or other online retailers. This is how a book grows legs. A positive review or endorsement is more valuable to the author than a single sale because it makes the book visible. Even a sentence or two is a giant help. Tip: Don't refer to the author by her first name in the review. Sounds like you're her mom or dad!
Subscribe to and interact with writers' blogs and tweets
Blogs and tweets are another way for authors to gain visibility. Good blogs provide information, inspiration, or entertainment for the reader with occasional information about a book launch or event. (Bad blogs are just ads.) Follow, like, friend, endorse...you're getting the theme here.