Startup Playbook

Y Combinator spends a lot of time advising startups. Though one-on-one advice will always be crucial, we thought it might help us scale Y Combinator if we could distill the most generalizable parts of this advice into a sort of playbook we could give YC and YC Fellowship companies. Then we thought we should just give it to everyone.
This is meant for people new to the world of startups. Most of this will not be new to people who have read a lot of what YC partners have written—the goal is to get it into one place.