This is really more of a post about my pet peeves regarding independent authors on various book sites, but I figure it's probably helpful for authors to know what readers don't want to see when they are promoting their books.
Joining a number of social book sites is a good way to promote your books, especially if you join discussion groups. Before promoting your books in a discussion group though, take some time to look around the group to determine what the group's policy on advertising is. Some groups don't allow advertising at all. If this is the case, please respect this policy and don't promote your books here as it will be considered spam. Many groups do allow advertising, but only allow it in a specific section of the group. Please respect this and don't post advertisements outside of the designated section or it will be considered spam. If you've looked around and a group doesn't have any policies against advertising and doesn't have a designated advertisement section, then feel free to promote your books in the main group section.
Don't promote your books too often. Even if you stick to groups that allow advertising and only promote your books in the designated areas of the groups, promoting your books too often still looks like spam. Also try to get involved in the group discussions. This doesn't bother me much, but some people aren't very receptive to authors who join groups for the sole purpose of promoting their books.
If you are having a sale or a free giveaway for your books that only lasts a few days or less, please give advanced notice before the sale/free giveaway starts. Many people don't have time to check the book groups for new messages everyday and some rely on daily or weekly email digests to keep up with the group activity. So unless your intention is to only get your books out to a limited number of people, I'd recommend giving at least a week's notice before a limited time sale or giveaway.
Make your ebooks available in as many formats as possible. A number of times I've seen authors offering copies of their ebooks only in pdf format. I know there are plenty of people out there that like pdfs for whatever reason, but for many people, including myself, it's the last choice of ebook format we'd want. There are many reading devices that either can't open pdfs or are difficult and awkward to read pdfs on. If you make readers go out of their way to read your books, they will be less likely to want to read them at all. Epub and mobi are two of the most widely used ebook formats right now and it would be good to provide your ebooks in those formats at the very least and branch out into other formats if possible. While epub and mobi formats can easily be converted back and forth, it would be preferable to provide your ebooks in both formats for those that lack the knowledge to do conversions.
Don't use unsuspecting readers as beta readers. Take the time to revise and edit your work before publishing and/or giving away free copies for reviews. If you want someone to beta read your work, then find a specific writing group for that, but don't pass off your books as finished and then use reader reviews and feedback to go back and put out a second revised edition of your books. This is unethical regardless of whether someone actually paid for your books or received free copies. If you want to look for beta readers in discussion groups, then make sure you are clear about your intentions.
Don't get bent out of shape if someone gives you constructive criticism. If you lash out at someone it only makes you look bad and readers are less inclined to read books from authors that act like asses. Whether someone is giving constructive feedback on your book, the book's cover, or your marketing practices there are only three acceptable responses. You can thank the person for their feedback, you can calmly explain why you chose to do things the way you did, or you can choose not to respond at all. Picking one or both of the first two options will make you look like an open minded gracious author. Picking the third option might not give the best impression, but it's certainly better than lashing out in anger.