What are the common features of religion?
There are many different organizational frameworks for identifying common features of religion. Emile Durkheim offered a sociological theory of religion. In this view, the salient common feature of religious experience is its ability to bind people to each other; through shared rituals, shared values, and shared transformative spiritual experiences. The result is that individuals come to view themselves not just as a collection of people, but as a group; a unit; a community.
A more contemporary model is that of Mindfulness Meditation teacher Shinzen Young. According to Young's view, religion contains a dual set of practices. One the one hand, religion contains practices that help a person go beyond self and the world (or see beyond). At the same time, religion also contains practices that help a person to improve self and world. Practices that help a person go beyond self and world are, for example: prayer, mystical practices, rituals. Practices that help a person improve self and the world are, for example: charity, discipline, and loving kindness.
In this view, self-help or self-development alone is not a religious practice, since (traditionally) psychological self-help contains no practices of seeing beyond self and world. Likewise, devotion to taking certain consciousness-enhancing psychedelic drugs doesn't count as religion because, while such drugs may help a person see beyond self/world, they do nothing for helping a person improve self/world.