The boosting process - potential profession pitfalls
This is relatively straightforward, and as described in the video above. However, there are some notable omissions if you have a level 60 character that you want to boost to gain the professions. We all know about the veteran bonus, that allows you to get maxed out, level 600 professions if you boost a level 60+ character.
But if you have a level 60+ character you're planning to use that hasn't yet learned any professions, you'll need to ensure that you have the professions you want learned before you go through the boost process. Otherwise the system will pick your professions based on the type of armor you wear. Once the boost is complete, if you have the wrong professions you'll have to submit a ticket to get them changed. We're not sure whether GMs are able to do that or not.
Once you're boosted
At the time of writing, new level 90s are being ported straight to the Timeless Isle. We do know that a change is being worked on to get them ported to their faction's Shrine instead.
.@oliviadgrace We're looking into changing the starting location for boosted characters to a Shrine. Preferably your own faction's.- Watcher (@WatcherDev) March 10, 2014
But, in the meantime, you'll need to be prepared if you're on a PvP server. The guards in the area were buffed via hotfix, but it certainly hasn't deterred groups of players from camping the spawn-in point, especially groups using the brand new 90s to farm Bloody Coins using the Censer of Eternal Agony.
Fortunately, your Hearthstone, which will be in your bag, takes you to your faction's Shrine. So if you find yourself under attack, use it to get out of there as soon as you can. Hopefully the hotfix will arrive sooner rather than later.
Other oddities include a bug that means you currently won't have your chosen spec learned if you happened to boost a character that had its off-spec active. Go to your specializations within the talent pane, and just double-check that your specialization is learned, because you'll be missing key abilities if it isn't.
What's more, and again this applies to characters boosted from above level 60, if you've maxed out crafting professions you may notice a complete absence of recipes. That's because the boost doesn't seem to include them. There's no word yet on whether this is a bug or intended, but regardless, if you want to make things you'll need to head over to the profession trainer and learn everything you want. For Enchanting and Jewelcrafting, this exercise costs around 1300 gold. So, you may well be better off just learning the max-level recipes and discovery recipes for now.
In the same vein, things like mage portals will not be learned automatically. You'll need to find a portal trainer in your home city and learn those. You'll also have no glyphs, no reputation, nothing of the sort. You'll need to pick up all these items to get started!
The first thing you'll want to look at is getting some better gear. We're going to do that on the Timeless Isle, then with Honor. Why are you farming honor? Well, it buys you ilvl 522 gear, without the tiresome random stats on Timeless Isle gear. Also, you don't need to do any PvP to get it, unless you want to! You can head over to the Horde and Alliance vendors to turn it in. You should do Timeless Isle gear first, simply because it's not predictable like Honor gear. Then you can use Honor gear to fill in the gaps in your Timeless Isle gear.
483 is just fine and dandy for gathering and the like, but if you want to get better gear, your first step should be to head, cautiously, back to the Timeless Isle. Ignore all the mobs, as much as you can, and open chests instead. WoW Insider posted a guide to every chest on the Isle, and using an addon like TomTom can make this a really easy task. You'll die a few times, but you should at least get several 496 epics and a Burden of Eternity that allows you to turn one gear token into a 535 epic.
After that's done, head over to the Shrine, and pick up the two quests from the NPC standing in front of the building, outside. Start with Meet the Scout, and complete the three quests that open up the Krasarang areas for both factions. Within the opposing faction's base, there are three rares which drop 275 honor points -- up to a maximum of 312 honor with the best guild banner -- and will do so once a day. Groups all get to loot them, so group up with same-faction players in the area to make it easier.
When you're done killing the rares, head over to the Shado-Pan Garrison in Townlong Steppes. It's in the North-West, near the coast. There, you should find the hand-in for Thunder Calls for your faction. You'll need to do the four scenarios to open up the PvP dailies, which you're going to do and earn between 577 and 656 honor per day depending on whether you have a guild banner. After all this, you'll have a total of around 1400 honor. There's also quests in Grizzly Hills that award around 200 honor per day, if you're feeling very dedicated.
It's worth noting that weapons, arguably the most important piece your character can get, will be a huge upgrade. The ones on the Timeless Isle, at 10,000 Timeless Coins for a one-hand or 20,000 for a 2-hand aren't really worth the grinding for an extra six item levels. The Honor ones are, but main-hand and 2-hand weapons have a points earned requirement, meaning you'll need to have earned 7250 Honor before you can buy them. Fortunately, the Honor off-hands have no points earned requirement so can be bought as soon as you have 1250 honor.
There's also some gear available from other sources. The quest Path of the Last Emperor awards 502 boots, for example, and if you're running dungeons and getting valor, you can get a 522 neck from the Shado-Pan Assault just for saying hi and giving Teng of the Flying Daggers or Ao Pye 825 Valor. You should also head to the lower level of your shrine and pick up then complete the Warforged Seals quest, with the lesser charms you'll inevitably have looted by now. Use one of those on the Celestial world bosses on the Timeless Isle every week for a chance at 550 gear.
There are many other things you can do to get higher level gear, and you should be looking at getting started on your Legendary quest chain if you're planning to do any serious raiding. But this is the way I find most efficient for getting a new 90 into reasonably good gear with the minimum of RNG and frustration. Please note, this is not for a leisurely amble, not for seeing the world and experiencing the story, not for discovery and wonder. It's to get you into decent gear as quickly as possible.