Considering as I haven't dated much, I don't have much authority on this topic. But I will say that being a devout Christian should be at the top of the list. God should be a priority over all other things, including work, relationships, and hobbies.
From my limited experience, I did date an atheist and was very close friends with an atheist. Needless to say, there is a very good reason God commands believers to be unyoked with unbelievers.