What's a lifehack related to books you think everyone should know?

I'm starting to get serious about reading books and already have a large number of books waiting to be read. But before I continue, I want to know lifehacks that can help me buy, read, sell or simply handle books.
Little things you know that could benefit other people too.
I'll start with something most on this subreddit know about but newbies might not. Goodreads. Website where you can check ratings, add books to your reading list, specify the date you read the books and write comments about them.