Well the answer of this question is relative to what religion you're talking about, what their version of heaven is and what the terms for getting there are, but I think that if you follow the doctrines of your religion then you should find yourself in heaven when the time comes.

The problem is that the doctrines and holy books of every religion are open to interpretation by everyone who reads it. The message that you see may not exactly be the same message that I see and as such people will often see war where there's peace or see blue where there's red.

I also believe that it's not everyone that is religious that will go to heaven or at least their version of heaven in their own religion. I've seen cruel hearted human beings who justify their cruelty by saying that it's "God's work". Just look at the war on terror, millions of people have been killed and the perpetrators truly believe that killing innocent women and children will take them to heaven.

The Christians killed millions in the past under the pretence of "God's Work" and there isn't a doubt in my mind that the people who were involved in such are NOT in heaven.