I missed out on about a week of MoP so far because of travel, so I'm not exactly cutting edge. Still I thought it might be good to have a rundown on what and how I've been gearing up.
Step 1: I bought the crafted gun (not terribly cheap) and a few cheap items off the AH. I didn't dip into PvP gear right away.
Step 2: I visited one of the MoP Justice vendors and dropped as many Justice points as I could and filled the really bad holes first.
Step 3: I realized ZOMG Brewfest trinkets and did that until I had the appropriate one and another just for the possible need. You can do this at level 89.
Step 4: I kept queuing for instances and doing quests. At some point my queuing started becoming heroic queuing. My goal for quests is to clear out as many zones as possible. Since there isn't much of a cap on dailies, I'm not particularly worried about falling behind there. I managed to get about 7 hours in one day and got a lot of nice 463 upgrades.
Tip 1: I had just bought a new Justice item and got into an instance in 15mins. We cleared it pretty quick and I got an upgrade over the Justice item I had just bought. I was a little bummed because I had enchanted it. But then I noticed that I still had an hour to return it to the vendor for a Justice point refund. And it worked. I'm sure the same thing can be done with PvP gear.
Step 5: I filled in a weak spot with a PvP boot upgrade, nudged up my iLevel with one final Justice purchase, and managed to finally get a heroic helm (with the meta gem slot). This brought me to i459.
Step 6: Gem, enchant, and reforge everything.
Tip 2: You can equip junk you will not use in a LFR raid just to be eligible to queue. I swapped out my i463 heroic agility trinket for an inappropriate i470 Brewfest trinket and was able to queue for the LFR instance. I suspect that the overall item level of a character is rounded down. In any case, as soon as I was in, I switched to the right trinket and it didn't boot me or anything.
Step 7: I ran the LFR bosses and scored a belt. I'm not sure if the quality of LFR is good now but it didn't hurt that I was with a guild tank another good DPS and good healer.
Step 8: Fight the Sha worldboss with 39 other people. Win nothing, but collect the quest item from the boss to get a nice pair of boots.
Step 9: Ran a whole bunch of quests and closed out two more zones and opened up the
Golden Lotus Faction and the Gate.