What does religion do in your world? How does it drive world events? Does it effect and influence politics? Are the gods of the inhabitants of your world real, or only a mythology created for an alliterative motive?
In Elidamara there are many religions, but in Estorad, where the first book Shadows of Virithimis takes place, there are two prevailing religions: Ker Ma’Ral and Margrism.
Ker Ma’Ral is the older of the two. It was gifted to the Quelarian from their god Madriel. It is a belief in two gods locked in a never ending struggle that directly effects the world, as Madriel’s counter part, Emeron, has taken a physical form twice in their history.
Margrism is the predominate religion in Estorad, spreading east from the Kingdom of Etermith. It is the belief that the lesser gods spawned by Madriel, or Amara, are divine beings that intervene in peoples lives and oversee harvests, life, death, birth, love, etc. Followers of Margrism do not worship Madriel, as they do not believe she directly intervenes in the lives of mortals.
In Elidamara the acts of Gods do actively play a role in the world. Religious leaders bribe government officials, and different religious groups fight each other for dominance.
Having these facts when designing your world can help give it a feel of a real place. Two dimensional religions and traditions can feel fake and forced. Even if your readers never see the majority of what you know, it will always seem more realistic than if you just slap something together as you go.
How do you incorporate religion in your world? How many gods have you created in your spare time?