This is all in the "my humble opinion" department, hence "shoulds" instead of "musts." I've been designing websites for over ten years now, and I've developed specific criteria for an effective author site. Readers expect certain things from us, and when they're looking at the site of an author they haven't tried, there are several key elements that will draw them in and keep them on your site long enough to maybe sell a book.
I chose five items that I consider important to have above the fold on your website. By that I mean they should be on your home page, things the visitor sees at once, not a click away or a long scroll-down away. Remember that you have maybe two seconds to capture the attention of your visitors. These five elements aren't the only important things to have up top, but the first three especially are crucial.
To see how well Ninc members' websites meet these criteria, I conducted a random and unscientific survey of 50+ sites listed in the Member Links section of ninc.com. A couple I wound up not including in the totals, because there was no website at the end of the link (fix it, guys!). However, cudos to the author who put up a "coming soon" placeholder page that included three of these five items.
1. THE COVER OF YOUR LATEST BOOK
This and number 2 are the most important items to be front and center on your website. Out of fifty-odd Ninc author sites, 38 had a current book cover on the home page. Make sure your cover image is large enough to see easily. I recommend at least 2 inches wide (or 150 pixels). Link the image to a page with more information about the book, including links for online purchase. And yes, I do want to see a book cover up there even if it was released a while ago!
2. YOUR PHOTO
Readers are visiting your page because they want to know a little about you. Be friendly, show them your face. Only 28 of the author sites I visited had the author's photo on the front page. That's just over half. Many of those that didn't had great-looking photos on the bio page. Don't be shy, people! Move it up front.
3. CURRENT NEWS
This is the age of instant gratification. Keep your home page looking fresh with a tidbit of current information. Doesn't have to be a lot: when a new edition will be out, your next appearance, a link to your latest (recent) interview. Something that lets the visitor know the site isn't stale. Ideally, the news item should be no more than a month or so (three at the most) old.
4. LINK TO YOUR BIO
This one was the most common on Ninc member websites. Out of 50, 48 had links to an author bio. Well done, folks!
5. LINK TO YOUR BLOG
At 17 out of 50, this was the least common element on Ninc websites. That's OK—not everyone has a blog. If you do, though, or if you participate in a group blog, be sure there's a link to it on your home page. Why is this one important enough to be in my top five? Because it's one of the first things people look for when they want to know more about you. And that's not only readers; it includes that editor or agent who has your proposal on her desk and wants to know who you are.
A couple of home pages were blogs, which is fine as long as it still includes your photo, book cover, etc. This is one way to make sure your front page shows current news. I'm seeing more and more websites set up on blog platforms such as WordPress, Typepad, etc. Using a blog platform allows you to update your site yourself rather than paying a poor, starving, part-time web designer and author to do it for you. (But if you need help setting it up, keep me in mind. Affordable rates, and discounts for Ninc members. )
Some of the pages I visited had links to other very good features: press kit/media page, newsletter, discussion group. All good ways to provide additional information and keep in touch with your readers. If you're a high-tech person who Twitters and RSSs and all that, make it easily availalble to your fellow techie (short attention span) visitors.
Your website is an important marketing tool. Make sure it's as effective as possible by incorporating these five key elements. You'll be glad you did!