[madnak]

Logically there is no way to gain such insurance, as the number of possible gods who will reward you for being true to yourself is the same as the number of possible gods who will reward you for paying lip service. If you believe that you know something about the afterlife, then you can make informed decisions based on that knowledge. Unfortunately, we can't help you much - we atheists either don't believe in or don't know anything about the afterlife, and the theists have their own specific views on the subject.

If you know nothing about the afterlife, then there's nothing you can do in life to affect your chances, logically. Still, I would say that being kind and loving, making the world a better place, and finding a sense of personal peace and fulfillment won't hurt. If you want to maximize your chance of heaven, living a good life in the here and now is the best start.