We love checklists. They are one of the best ways to keep us on track. Like packing for a trip. Planning a party. Getting taxes done. But there is no checklist for your life — unless you write it. There are plenty who will differ: When are you going to have kids? You don’t own a house yet? You should get a master’s degree. But only you know what you really should do. Here’s how to figure out what that is.