Second part of a guide for those that roll or reroll a paladin. The first part of the guide, addressing levels 1 to 58 can be found here: Paladin Leveling Guide (part1), second part for lvl 58 to 68 is here: Paladin Leveling Guide (part2).
This guide is more targeted for those that already have a lvl 80 and can support their alt, but most of the tips can be applied by anyone.
Paladin Leveling Guide (part 3, your time in Northrend)
The basic advises from the first guide are still valid, I'll rewriting them here because you should always keep them in mind while leveling.
The first tip, which is common to all leveling guides you'll ever find is: maximize your damage output. Don't try to gear for survival, the game isn't that hard most of the time and you'll want to down mobs fast.
The second tip is, try to get a good leveling guide if you want to. If you're new to the game, enjoying the discovery is probably the best thing to do, and using Wowhead to search when you're stuck in a quest will be enough. If you're a bit tired of the vanilla content, or want to reach 80 much faster, then leveling guides are for you. I used Jame's Leveling Guides for my 3 last characters, from 1 to 78 (last levels are not yet in the guide but really not hard to do) both on horde and alliance side, and I strongly advise them.
Ok, now let us start with paladin stuff. You can find all the paladin skills by level on Wohead here, if I'm not direct linking a skill, go there for more info.
I've written my views on leveling as a protection or holy paladin in Paladin Leveling Guide (part2). Though a dps (retribution) spec will level you faster, if you intend to tank or heal at level 80, I advise you to get the dual spec talent (that you can buy for 1000 gold) and try instancing with this spec. Retribution will be better for solo questing, but you'll find a group easier as a tank or healer, and will get used to what you want to play later on with your paladin.
The 2 weapons that will bring you to 80
When you arrive in Northrend, your first objective should be the Axe of Frozen Death, it's a @H Axe that you will probably keep until lvl 75. It is roughly equivalent to the 2H axe dropped by Prince Malchezar at the top of the Karazhan tower, which was a beauty coveted by many arms warriors.
It can be reached completely solo by horde players, you will need a group of at least 3 with a good healer to get it on the alliance side (trust me the last quest on the alliance side is suprisingly hard).
If you follow James guide, you'll get it fairly late especially if you're alliance. I'd advise you to get it earlier and get it enchanted with a +85 attack power as you'' play with it for a few levels.
When you reach lvl 75 it will be time for you to go to Zul'Drak if you're not yet there and do the Arena of Anguish series (remember the Arena of Blood in Nagrand, it's the remake) to get your De-Raged Waraxe. Once again enchant it with a +85 attack power, you'll probably keep this axe until 80.
The arena can be done with a good group of lvl 75 characters, but you will often find people helped by level 80 characters in full epics doing it, if you can find an easy spot, take it by all means, this axe will be your best friend for a long time.
If you're searching for a Holy paladin weapon, it'll not be too hard to find decent quest ones. If you want a good one, I'd advise you to befriend the Kalu'aks that have a very nice lvl 78 blue healing mace, you can also get nice healing weapons in several instances.
As for tanking weapons, the choice is much more scarce. You'll probably have to use a one handed dps weapon (at least there are some with endurance & expertise like this one) until lvl 74. At lvl 74, get one or two friends and go get the Ragemane's Flipper (elite quest lvl 74). You'll probably keep it until lvl 80.
Where to go and what to do when you arrive ?
(zones to level in)
Not considering the notes about getting your weapons before (it all depends if you're using an heirloom weapon) here is the order I'll advise you to follow in Northrend.
I'll advise using Jame's guide in that order:
Howling Fjord : lvl 68 to 70
Start with Howling Fjord questlines, until you reach quests which are lvl 71. It should be at the end of the "pirate" part of Jame's guide. Try to do the Utgarde Keep instance before leaving the zone.
Borean Tundra : lvl 70 to 71/72
Switch to Borean Tundra by Kalu'ak tortoise boat, and do all of it and the Nexus instance.
Howling Fjord : lvl 71/72 to 73
Back to the Fjord, finish the quests, do the elite ones if you can, do the Utgarde Keep instance if you've not done it before.
Dragonblight : lvl 73 to 74/75
Dragonblight is your next zone, there are two instances in the zone, you can do them whenever you find a group for them. This zone is huge, and there are several elite quests that require a group but are nicely rewarding (follow Jame's guide).
Zul'Drak : lvl 75-76/77
Zul'Drak is a good zone to level in, you have the Drak'tharonKeep (lvl 74+) and Gundrak (75+) instances into it, and the Arena of Anguish (see before).
Grizzli Hills : lvl 76-77
If you're not yet 77 then go to Grizzli Hills and grind quests until you are.
Scholazar Bassin : lvl 77-78
Do the Nessingwary quests if you want the achievement, do the Oracles/Frenzyheart quests for the faction rewards if you're not into achievements (they start with this quest).
Storm Peaks & Icecrown : lvl 78+
These zones are full of great quests, that will provide you with items still useful at lvl 80 and are very nice story wise. You will also be able to start your Son of Hodir faction grind for your shoulder enchants (with this quest).
The real new skills until 80.
The first one is Divine Plea at level 71. That will strongly change your mana regeneration, and can make leveling as protection doable (though a little slow still). This skill gives you back 25% of your mana each minute.
The second one is Shield of Righteousness at level 75. Only usable with a shield, this is another help for protection leveling, and a huge aggro boost if you're tanking.
... and now you reached 80, good job, now what to do ?
That will be part of a next article where I will try to advise the fastest path itemization-wise, to reach up-to-date raid status as soon as possible (I went from fresh lvl 80 to a gear roughly ok for Ulduar 25 in 2 weeks on my druid with the patch 3.2 token fest).