The most important thing to remember about being a Paladin is that you have 3 roles that you can handle. Everyone can DPS, but not everyone can heal or tank. You can do all of them, though the latter two you should specialize in if you're interested in handling them full-time. That's one aspect that is usually missed by most players. Keep an eye on health bars and heal if your healer is overtaxed, keep an eye on Decursive (don't have Decursive? Get it. NOW.) and click off debuffs. Drop a Blessing of Protection on a squishy that's got mobs beating him to within an inch of his life.
Paladins are inherently a support class, but people take the image of 'support' as being some hanger-on that barely contributes enough to stick around. Far from the truth - support means you're what makes the gears turn. You make everything run better, everything smoother, and while people may not always notice, YOU know you got the job done, and that should be what matters. Quality Paladins get re-invited to groups, whatever their spec.
Thus, your goal is not to lay out the best damage you can possibly do at all times, your goal is to help the group complete its task. As a Retnoob, of course, those two goals are usually aligned, but if the healer gets nailed or the mage has mobs all over him, sometimes these goals diverge, and you have to pick up the healing slack or slap on a shield and piss off some adds.
Which brings me to point #2. All Paladins have at least 3 gear sets. As a Paladin you should have a healing set, a DPS set and a tanking set. So if the next pull has a couple of adds that can't be CC'd, you can take on the task of keeping them busy by slapping on tanking gear, or if you're on Prince and your raid wants 3 healers for the task, you can throw on the healing gear and save a few lives. I know, I know - you have no bag space. You want to be up front beating up stuff. Preaching to the choir. Learn to live with it if you want to be known not just as a guy that's good on the damage charts, but as a good Paladin. Who just happens to beat the ever loving snot out of anything that gets in his way.