Religions are, basically, answers to the question “How ought I to live?” or similarly “What is the Good life?” Every television show, movie, book, and so on, contains some (implicit or explicit) answers to these questions. This is one reason why media often is at odds with various kinds of religious ideas – they are overlapping in what they are doing.
Religions store up a body of ideas, beliefs, and practices that are believed to be answers to those questions. Within a religion, there are usually many different kinds of traditions, churches, services, and so on – many different ways to answer that question – although these answers may be more similar than answers compared from within a given religion and within some other tradition.
It seems to me that the way to figure out how good of an answer a given approach is (and different approaches may be better for different people in different circumstances), is to look at the people practicing it. (I am thinking here of more organized answers, such as religions give, and then secular answers as well.) Basically, does it work well on the whole – does it work better than the alternatives available? Does it work well for this sort of person, but not this?
This requires some exploring – actually seeing what the fabric of a given person or peoples’ lives are like, and then comparing one approach (whether ‘religious’ or not) to another. It is often not easy to do this, and it is not largely theoretical, it is empirical. That is, one must go out and see whether certain approaches work, and how well, and for what kinds of people.