It can be very stressful deciding how to support your favorite authors.
Do you pre-order on online retailers? Or wait to buy the book from an independent bookstore?
What if you want to go to a signing event and the bookstore sells "tickets" that include a copy of the book? Not everyone has the scratch to buy two copies. Not to disparage the booksellers--events take labor to run, and I don't mind buying a "ticket" especially when it includes the book.
So what do I do?
I am not a big fan of Amazon, despite starting as a self-published author who used Createspace and the Kindle Select program. I tried all their plans, I used Amazon Associates, too. I'm not very satisfied as a customer; they have gone the way of eBay, there's so much junk that you can't wade through it. And I'm not even talking books, but when I want a phone case or a cable, home goods, or whatever, I've had to send back so many items. Then there's their business practices. Not gonna judge if you use the 'Zon but I don't. I moved the Protectors anthologies and my own books to Ingram distribution for print, and Draft2Digital for e-books. They distribute through Kindle, but I'm not directly using Amazon anymore. Their reporting was terrible, too.
But they will not be ignored. So I pre-order books there to help authors whose work I want to support. And then sometimes I cancel that order a week beforehand and order it at my local bookstore or get it at a signing event. Maybe that makes me evil. Maybe I don't care. If Barnes & Noble is your local bookstore, use them. Pre-order there, especially if they don't carry the press it's published by. That can help. Maybe they'll carry the next one.
As for Goodreads and so on, I try to rate every book I read there. Even though Amazon owns them and now charges $119 to $500 for a Goodreads giveaway. Which is downright horrible for small presses and indie authors, who have to pay for the books and postage as well, turning a $50 proposition into a $180 one. But there's more! Now giveaways will annoy readers by automatically putting them in your Want to Read list (previous it was optional) and sending you a notification to Rate and Review the book (and give the author one star because you are angry at the world!!!!!) a few weeks after the giveaway ends. Reminding you that you lost, and making you angrier.
Another thing I do is make sure the book is at my local library. Many libraries have online catalogs and if you are a member, allow you to suggest books if they don't have them. So this is a free way to help authors and read their books if you can't afford to buy them, or are on the fence.
How about social media? I'm not convinced that retweeting or sharing a writer's promo links has much effect. I've had links shared by people with 180,000 followers and it resulted in zero engagement, clicks, or sales. Maybe if Stephen King does it with his 6 million followers, you'll see action. The best thing a reader can do is spread word of mouth, make their own post on social media about how much they enjoyed a book. If you're not a book collector, give your used copy to a friend or the local library.
I'm not a fan of the memes "how to help a writer!" that turn readers into combination publicists, cheerleaders, and therapists. You bought the book, thank you. If you want to review it, thank you some more. But I really don't think you owe the writer anything. Just as the writer owes you the best book they can make at the moment, after that, everything is lagniappe. You come to a book event? You're awesome. Thank you. Every writer deals with empty seats, and it's a good time to chat up the booksellers when it happens. Or if only one or two readers show? They get a more intimate experience, as they share cookies and cheese cubes with the writer.
So, thank you for whatever you do, readers. If you like a book, spread the word. As I've said before, if you don't shout out about what you love, don't be surprised when it's gone.