I usually grab the early religions like Buddhism and Hinduism and Judiasm. I then try spreading the first one I get to *most* of my neighboors. I then try either spreading the other religion I get to the one or two (usually decently ranked) other civs. If I don't get two religions I basically try to spread my religion as quickly as possible to make my religion the dominate one. Basically I try to have one or two civs have a different religion than me and have everyone else have my religion. This makes it so that I can feel safe in terms of war, If I want to gain more territory via war I can do so with the help of many civs and avoid those pesky "you declared war on our friend" -1 relationship penalties. In my current game I went religion crazy and spent nearly all my research on religion. However, this ironically made it so that I couldnn't spread one religion with missionaries because my military became so weak that when two barb warriors came it was a huge threat to my empire and I was nearly wiped out (I know its pretty pathetic). This caused me to instead of building missionaries build desparetly needed warriors. Normally I would be able to build two or three archers and be fine but I hadn't researched archery and I therefore needed to build alot of warriors. What happended was that my religions spreaded randomly(through trade routes) and at one point every single civ had a different religion and everybody was annoyed with each other. After a while almost evreyone converted to confusionism because that happended to randomly become dominant and then everyone switched to christianinty (it happended to become dominant) and then a few turns later switched back to confusionism, etc. ,etc., I think there was a total of five major switches before I stablized the major religion with missionaries (it happended to be confusionism because at the time I got a great prophet that was the major religion- by 1%- and I built that shrine). In other words trying to control religion is great, just make sure you actually control it. An example of how controlling religions can benfit you is that in another game I had were I completly owned religions and was able to declare war and destroy 5 civs without a single "you declared war on our friend" penalty (I actually didn't start off with having 5 civs have one religion and the others have the other religion I at first had only 2 civs with a different religion; destroyed them; and the converted one civ destroyed them, then converted the other civ, then destroyed him, and then the other one founded a religion and I then destroyed him-and this was on deity occ challenge, jk it was just a normal warlord game)