WoW Paladin help, oom often?

So, I've played WoW for awhile, and this paladin was one of my first characters on this account. He's lv 69 (heh) and constantly running out of mana. He's retribution, and I'm pretty sure I have the right talents set up. (if someone could give me a rotation that may also help) I haven't wanted to level him for a loong time because of that, he constantly runs out of mana, dies, and becomes frustrating. So, if someone could give me some tips on NOT running out of mana with a ret pally, that would be nice. I do want to level him to 85 because i know that paladins are fun.