Be in movies. Then join Twitter.
I have nothing against Anna Kendrick. She's funny, she works hard, she sings well, her lip-syncing skills are highest-level. She deserves her success, and I'm not saying her tweets aren't funny. It's just, well, there's a pattern, which you'll pick up on if you keep reading but forgot that I told you about it: in order to get a book deal, you really have to get famous in some other format than book-writing because why would you take a chance on people who have devoted their lives to the art of writing when you could pay a celebrity Osteen-level amounts of money to paste all her tweets into a Word document?
Additional author's note: sometimes I'm going to write about people I hate. Sometimes I'm going to write about people I like. Sometimes I'll write about people I don't give a shit about. So if you're Anna Kendrick, I'm not mocking you; I'm mad at the publishing industry, not you.