1. When you sign up as a Goodreads member, don't use your best email
Because you WILL get junk mail. Lots and lots of it. Many authors now use Goodreads to promote to their friend list, and it all goes straight to your email inbox. Unlike Facebook, where the promotions go on a news feed that you can ignore.
Best to use a "junk email" address for Goodreads membership. If you are fed up with the constant stream of promotions clogging your inbox, consider changing your sign-in email to a little-used one rather than cancelling your Goodreads account. Although now that Gmail has divided their inbox into "promotional" and "social" that may just solve the problem.
2. Watch out for friend requests from people who have tons of friends but very few books. I don't get these people. Isn't Goodreads about the books? Well, yes, I do get them. They're on to push their books (see #1 above) rather than to read and review books. I used to accept friend requests from anyone who sent one but lately I've ignored these types. I don't need more pushy people trying to sell me their books, or inviting me to events I'll never go to.
3. Add a nice photo to your author profile, link to your blog, completely fill out the biographical information. People like to learn about authors, especially if they read your book and enjoyed it. Make your author profile page as complete as possible. It's not so important to have hundreds of friends-- you'll see popular authors with none at all actually, but their fan list is large. Sign out of Goodreads to view your profile page objectively and see what you think!
4. Add quotable quotes. I came across a feature recently which I think is very cool, and really makes the profile page look professional and complete. If you scroll down toward the end of the page there is a place to add quotes. On mine (here) I added quotes that readers had frequently highlighted in the Kindle versions of my books. If you look to the right side of the page it will say "add a quote." Quotes can be added by anyone, not just the author.
5. Professional review etiquette means that when you write a review, be honest without being rude and hurtful. When you read a review on your own book, please refrain from adding a comment. Even if it's an amazing review and you want to say thank you, don't! And if it's a poor review and you want to defend your book or respond, don't! It is entirely unprofessional for authors to respond in any way to Goodreads reviews.
Okay, these are my Top Five Goodreads tips. I'd love to hear yours. There is so much more to be said! Can authors maximize Goodreads and still be professional about it?