It's time for the old pre-raid gear grind! Time to run heroics, get hit-capped, and replace all those quest greens!
Things have changed a little since Cataclysm, though. The old Heroic/Justice Point/Valor Point setup is a whole new beast, and you should adjust your thinking if you want to efficiently and effectively gear up.
First of all, kill the world bosses as much as you can. The Sha of Anger will give you epic boots (via a dropped item that starts a quest), and if you're lucky, you can get tier gear, or high-ilvl PVP gear, both of which will absolutely be worth using as you foray into Mists' initial raids.
Secondly, VP gear and crafted epic gear will be amazing options, like always. However, your access to these is limited due to VP/gold cost (nothing new here), but for the VP gear, you'll also be restricted by your reputation with the various Pandaria factions. So check out the various groups and see which pieces you need from them, and at what reputation levels, so you can prioritize doing their dailies. Also, be sure to complete any normal quests this faction might have, since rep is rep!
And of course, LFR gear will be solid upgrades (though impossible to truly plan for). Not as good as VP or crafted epics, but still pretty damn good. Run LFR as soon as you can, and every week, and take whatever you can get. Personally, I wouldn't spend tokens for extra loot though - save them for world bosses or for your actual raids. (Your mileage may vary, of course, depending on how many tokens you have/get the chance to use on non-LFR content.)
After this is where it gets interesting.
In Cataclysm, you wanted to run heroics for gear, JP and VP. Well, you'll still want the heroic gear and VP, but the stuff you can purchase with JP now is basically garbage, and you shouldn't buy any of it!
Heroic chest on the left, JP chest on the right.
Heroics drop ilvl 463 gear, while the JP vendor gear is ilvl 458, which means the stats will be slightly higher on the heroic gear. However, a more significant difference is that many of the heroic pieces have sockets (and socket bonuses), which is a HUGE difference, since Mists' gems are so powerful. Even a green-quality, non-perfect gem is worth +120 primary stat, or +60 primary/+120 secondary.
And now we come to PVP gear, and its infamous raid/PVE stigma.
Let's get one thing straight. You should absolutely check our your factor's PVP vendors and see what your options are. Yes, the PVP gear is only ilvl 458, and it's *gasp* PVP gear! /mock horror. But don't be fooled! PVP gear is absolutely fine for PVE now (with two PVE stats like any PVE piece), and anyone who still thinks it's unsuitable for PVE content is either way out-of-date or just plain dumb. (Or both.)
(Exception: tanks. Sorry guys, you are - like always - out of luck here, since PVP gear doesn't have tanking stats.)
However, not only is PVP gear acceptable, but some of the PVP stuff is actually just as good as the JP or heroic-dungeon equivalents, DESPITE the lower ilvl. And in fact, some of the PVP options are flat-out, 100% better.
Why? Two simple reasons. Gem sockets (and socket bonuses), and 2pc/4pc bonuses.
Remember what a big difference a socket makes? The same holds true here. Take a look at these two strength DPS belts, one from a heroic, one purchased from the PVP vendors.
At first glance, the Grenadier's Belt appears to have +100 more strength, and about 150 more secondary stats. Clear winner, right? However, the PVP belt has a socket, with a +60 strength bonus. Throw a +60 strength/+120 hit gem in there, match the socket bonus, and suddenly that's an additional +120 strength/120 secondary, bringing it right on par with the PVE belt. Or, use a good quality +80 strength/+160 hit gem, and now the PVP belt is superior.
So if you can't get a specific heroic piece to save your life, check your PVP options, because you might be able to convert that pointless JP into Honor and simply buy an upgrade.
(Of course, if you intend to actually PVP, then making these purchases is even more beneficial, since you'll get double-use out of the gear.)
Convenience isn't the only reason to check your PVP options, though. The other major benefit that many people are overlooking with PVP gear is something unique to this particular time in the expansion - set bonuses. This early in Mists (or any expansion), you simply can't GET your PVE tier set bonuses yet. But you CAN get the PVP 2pc/4pc bonuses. And some of them are very, very useful for PVE content.
For example, here's the Holy Paladin PVP set:
Obviously, ignore the PVP power/resilience bonuses, since those are useless in PVE. But 10% extra Holy Shock healing? A free charge of Holy Power whenever you cast a 3-charge Word of Glory? Um, yeah, those will just be slightly useful in PVE content, wouldn't you say?
For reference, Holy Shock makes up anywhere from 10%-15% of my healing on any given raid night or specific fight. Having the 2pc set means that the bonus alone is roughly 1%-1.5% of my overall healing. Which doesn't seem like that much, but for context, consider that the extra +25 stat difference between good and great feasts that all the elite raiders have been freaking out about is about a 0.25% increase. (25 extra Str/Int/Agi when you already have 10,000)
Later on in the expansion, the PVE set bonuses will undoubtedly outshine the PVP set bonuses, so you would obviously prefer PVE tier over PVP. But at this point? When your PVE options HAVE no set bonuses? The PVP bonuses are pure extra goodness.
Finally, one last note about the PVP pieces, if you're trying to decide which pieces to buy to get your 2pc or 4pc bonuses. Remember that all the PVP hands have a small innate bonus by themselves. Some will be nice minor perks, while others will be useless. For example, the Holy Paladin hands increases the critical effect chance of Flash of Light by 2%. Pretty insignificant, but you know what? It's better than the bonus the PVE hands give me. (As in, no bonus at all.)
(Some of them are surprisingly nice, actually! The Retribution Paladin hands give a straight-up 5% damage buff to Crusader Strike, which is nothing to scoff at!)
Now keep in mind, I'm not saying blindly go out and load up on PVP gear because it's all amazing and better than everything else. You have to do some research. See what your set bonuses are, see what the socket bonuses are, see which pieces have more or less sockets. For Holy Paladins, the PVP stuff rocks. For your class or spec? The PVP gear might be awful. For example, the Frost/Unholy DK PVP 2pc/4pc bonuses are...well, pretty much crap when it comes to usefulness in PVE.
Added suck? The socket bonus is Resilience. So yeah, this is a clear example of when a PVP piece is NOT better.
In closing, the JP gear is terrible, the heroic gear is usually not bad, and the PVP gear can be either great or horrible. But when you're planning out your upgrades and pre-raid purchases, remember that PVP gear does exist and is a legitimate, sometimes amazing option. You'd be foolish to disregard it without at least doing a little research first.