I believe the problem for you is finding opponents that are actually tough.

As to prays, with my tatted pally I prayed when I was seeking an out my imm, when I was doing some preaching to other players, or when I was about to go into an insane fight. Which for me was usually going one on one with Satebos, there were other tough fights and losses, but those were far more random and so no time to stop and pray before hand. Besy location is the shrine if they have one, as lots of times they are in there if they are visible. Imms generally don't want to go vis and sit at market square to talk to you, temples are there cause its kind of a private place for the chats.

I don't think praying I've just done so and so does to much, generally I use prays if I am looking for an interaction that has a bit of a point. Ysaloerye was fond of picking me up and throwing my ass into her temple when she wanted to talk to me, and other times your imm may just enter a mob where you are for a fun little interaction. I'd say keep prays brief, do them when they have a point or when you need something (not please god save me type things-though that can work and sometimes they'll make deals with you in exchange for saving you) and really just be nice to the imms as they all (i think at least) receive general prays, so it can get kind of cluttered if everyone prays look at me I just killed a bunny.