I've heard this question asked by quite a few people, so I'm going to take a few minutes to tell you some ways you can help your favorite authors.
1: Review their books.
You don't need to leave more than a few sentences and a star rating, but taking the time to go to amazon.com and goodreads and doing just that is a good way to help other customers know what you thought about a book. Here is a very quick guide on how to choose your star ratings:
1: This book is absolutely terrible. It is full of editing editors. (Do you see what I did there?) The author took no care with the story. It's just bad. It is so bad you threw up in your mouth a little. It is so bad that you recruited a friend to read it with you just so you wouldn't suffer alone.
2: This book was pretty bad. Sure, you may now have thrown up in your mouth a little, but it was bad enough you winced. It's full of errors. The story line is abysmal. The only thing going for it is the fact that you know it could've been worse.
3: This book was okay. Pretty average. There were more errors than you thought there should've been, but you were entertained. You think that there are things that could be improved, but hey, that's life. It was a middle of the road book.
4: You thought the book was pretty good! It could be better, but you'd totally recommend this book to your friends. It may have some errors, but all in all, it was a pretty good read, and you don't feel like you wasted your money. You might even read it again.
5: This is one of your favorite books. It doesn't have any noticeable problems. You love the characters, you love the story, and you'd totally take a copy to bed with you and snuggle with it. It's a book you talk to your friends about. It's a book that sticks with you. It's a book that makes you think, makes you laugh, or makes you cry. Simply put: You loved it.
A short review can be something like… “I loved this book! The characters were interesting, there were twists and turns I didn't expect, and it kept me wanting more. <Character> was my favorite, and I really liked <this element> of <author's> writing.”
Anyone can leave a comment like that, and it shouldn't take you more than a few minutes at max to write something. Just let people know why you loved or hated the book. You don't have to leave monster reviews like I do. You really don't! Other customers often don't read the long ones; they want a general gist if the book might appeal to them.
2: Tell People About the Book
Social Media and word of mouth can be powerful tools for a fan to make others aware of a novel. Tell others why you loved the book, and give them a link to it. Give the book as a gift to your friends, if you can. Either way, let people know what you thought of the book, even if it is only a few sentences or a single tweet.
3: Tell the Author!
As a reader, I notice when other readers tweet or send a post to an author saying they loved the book. As an author, when someone does this for me, it makes all of the effort and hard work worthwhile. It may not help the author sell a book (although it might…) it does brighten their day! Some authors (like me) may only manage to mumble an embarrassed ‘Thank you!' but don't get discouraged by that — I can be a bit shy, especially when people start saying nice things about me. Other authors get bombarded so hard by their fans that they struggle to keep up, but most authors are really grateful every time someone says something nice about their books!
You matter, no mater how large or small your network is. Never forget that, readers.