Only invest in religion if you spawn near a faith natural wonder. Otherwise you a better off building an army to invade your nearest neighbor or protect against an early DoW.
What? Did you want to qualify that statement with anything at all, b/c it's def not a valid blanket statement, whatsoever. No, I wouldn't go so far as to take the Jungle Pantheon over it, but whatevs.
Also normally I try to save river jungle, and especially if the city is already set up well for food. Because I enjoy both the money and the science that those specific tiles will eventually make. Other people brought up chopping those down due to the defense danger it poses on your city. The way I see that is, you're going to need an army anyway, but they cannot effectively defend unless you build at least one road over that river regardless. So if you build a road/bridge around the middle of the river, your units will have the mobility to aggressively defend and not simply sit inside that city. Also if they are aggressively defending, they get to use that jungle themselves instead of the enemy.