In our excitement to make our websites clever and beautiful, we sometimes forget to think as a new customer who has never visited our site before and has no idea where to click to find out if this is a series or a standalone book. Don't make them look. The idea that if they poke around, they will figure it out is doing a disservice to your book sales. Show them a clear path to each task you want them to perform on your website.
Two examples of common usability issues are signing up for emails and easily sharing your content with other possible customers. These are two tasks you want to make as easy as possible because both help you grow your tribe. Make the button to collect emails easy to find, and don’t create a ton of drag by making your potential subscriber jump thorough a bunch of hoops like CAPCHAs and the like. Add sharing buttons so if someone reads your blog post for example, they can easily share it to Pinterest or their favorite social media platform with one click rather than having to copy and paste URLs.
One last thing I cannot stress enough, test your tasks. It can be as simple as inviting a friend to preform specific tasks on your website. See where they stop and struggle. Make notes and changes. It is easy to skip steps because we have the entire picture in our head and mentally bridge an information gaps that may exist. By having someone else do it, you will truly be able to identify confusing elements. If they pause at all, it is worth taking a second look at what they tripped over.