WoW Gold Farming Strategy: Un'Goro Crater

This guide is written with Un'Goro Crater in mind because that's where I farmed most of the time at levels 47-57 but you can apply most of every hint to your preferred zone.
With my shaman, I came to Un'goro Crater at level 48 a Saturday and left the zone by the next Saturday level 55 with more than 500 gold and a full paid enhacement set costing 300 wow gold and some goodies. I had one week of holidays alone, no GF, no friend since everyone was at work ... . Probably most everyone knows the information included in this guide, but I'll share and explain what I have done in detail, so it'll probably help someone.
These are a few key points.....
Profession: Skinning is a needed. If you have herbalism too (like me), it's just better. Miners can find some Thorium/Mythril Veins (not sure about Mythril) in Un'goro.
Mods: Download/install SellValue add-on. So you can see how much vendors will pay for your stuff. If it doesn't sell well and doesn't stack, destroy it. Auctioneer is good too to help you sell stuff at the right price.
Most Importantly: Create a toon and bring him near any AH and a mailbox. You'll need it! If you have time, bring him to level 6 (1-2hr) and take enchanting to disenchant everything that doesn't sell and sell the materials. By the way, humans/undead are faster/easier to bring to an AH.
Preparation
Check the price of Un'goro Soil and Power Crystals in AH, if they sell well, gather them. If Power Crystals don't sell, use them to buff yourself for free while you grind but only gather the one you need for your buff since they take valuable bag slots.
If you don't have the flight path to Silithus (like me before I knew where the FP in Silithus was), buy any supplie you think you'll need there (reagents, ammo, poisons, flash powder, etc.) and ask a friend or use a toon to send you back your stuff by mail so you get everything you need in the mail box (No shady dealer or reagents seller in Tanaris). When you empty your bag in Gadgetzan, fill-up with the supplies you need from the mail box.
Set your Hearthstone to Gadgetzan or Cenarion Hold if you have the flight path.
Tips/Thing to Remember before go Bags Slot = MONEY
Take only the supplies you need for the time you fill your bag with stuff to sell. IE for rogue, usually 1-2 stacks of each of your preferred poison is enough. Too much supplies = less bag slot for stuff to sell.
Use no more than a bag to take your stuff (even a bag is probably too much anyway), every other slot should be for drops.
No humanoids -> no cloth drop -> bandages become expensive there, but you get a lot of meat so you can cook it. If possible, gather only the meat you really need to feed yourself (or your pet), and cook them when you empty your bag so you don't need to bring spice or wood (for campfire) with you.
Don't group. So you don't have to share anything. I know, it's selfish.
If you are Warlock, you lost a lot of place with Soul Shard, specially with a Soul Bag since you lose a bag for loot. Try to use an add-on like ShardTracker or Necrosis, these add-on manage your shard and once again try to not store more shard than you need. With that, you can use a normal bag to put your loot and your shard in.
NOTE - If you are lower than level 53 start from Tanaris, the mobs are level 49 near the Un'goro entrance by Tanaris, after level 53 use Silithus entrance as mobs are around level 54-55 there.
Un'goro Crater
Kill EVERTHING. If it's a beast, skin it. Herbal mobs have a little chance to drop some herbs. Many mobs have a chance to drop Un'goro Soil too. Thick/Rugged Leather sells for 1g+/stack.
Un'Goro Soil. Usually Soil sells for a 3-4g a stack on my server. You can find them everywhere. Another use for Un'goro Soil is for the repeatable quest "Morrowgrain Research" available in Darnassus/Thunderbluff or Feathermoon Stronghold (Alliance). The quest say "Use an Evergreen Pouch with a Packet of Tharlendis Seeds and two Un'Goro Soil samples to try and cultivate samples of Morrowgrain." You have ~20-25% chance to get Morrowgrain and you need 10 for each time you complete the quest. This quest build your reputation with Darnassus/Thunderbluff and like every item who can build up reputation, Morrowgrain sell for gold. If you don't get Morrowgrain, you still get random herb to sell. *Note If you plan to build up your reputation with that, turn them to Feathermoon Stronghold, someone told me they give the same amount of reputation for only the need of 5 Morrowgrain. There is not equivalent for the Horde. Since the patch 1.10, tailor can now use Morrowgrain to make Cenarion Herb Bag used by herbalist to hold their herb.
Power Crystals. Raw Power Crystals can be used in Blacksmithing. You can gather them for the quest "Crystals of Power" from J.D. Collie in the cavern at Marshal's Refuge for a good XP bonus and "Making Sense of It" to get the Crystal Pylon User's Manual. This manual tell you some info about how to use Power Crystals and Pylon in Un'goro Crater. By combining the right Power Crystals with the right Pylon, you can create up to 4 kind of awesome buffing crystal, Crystal Restore (Heal over time 670hp/15sec, 3min cooldown, share the same cooldown than Healthstone but not healing potion, Northern Crystal Pylon), Crystal Force (+30spi for 30min, 10min cooldown, Eastern Crystal Pylon), Crystal Ward (+200 armor for 30min, 10min cooldown, Western Crystal Pylon) and the last one for tank to get easy aggro Crystal Charge (Small Area-of-effect (3yrd) for 383-517 fire damage, 1min cooldown, Northern Crystal Pylon). These crystal are also used in many Librams quests.
If you are an herbalist, you can gather many herbs which sell very well at the Auction House.
Do some quests if you want, but NEVER waste your time travelling outside the zone for a quest while grinding. It's never worth it, even for the XP.
If it takes more than 45 seconds to kill it you're probably not optimizing your time, find easier mobs and come back later.
Gather Bloodpetal Sprout in the zone and from the mobs. You can turn them to Dadanga for the repeatable quest "Dadanga is Hungry!" at Marshal's Refuge. You get a small amount of XP and a Small Brown-wrapped Package as reward which include some food, scrolls and goodie to help you grinding. If you are lucky enough, you can get the Recipe: Elixir of Brute Force who sell very well (hundred gold?) in the Auction House.
When your bags are full:
Hearthstone
Sell stuff to vendors
Send everything else to your alt-bank. Don't waste your time going to the AH, it's too far.
Take the reagents/ammo/poison needed only.
Run back to Un'goro. Rinse and repeat.
Note - If you don't have too much stuff to send to your alt by mail, use the local vendor at Marshal's Refuge.
Good Points
Nice XP (if you do it at same level I've done it). At the end I was able to make around 30k XP/hrs (not rested). You only need to find the right mobs to kill. For instance, if a mob level 50 takes 30sec to kill and give ~200xp, you get ~400xp/min, ~24k XP/hr. If the level 52 takes 1min for ~300xp/min, you get ~18k XP/hr. We're talking about of 6k/hrs, 25% less effective in XP grinding.
Nice gold. Thick/Rugged leather sell for more than 1-2g/stack. Un'goro Soil is supposed to be around 2-4g/stack.
No farmers there.
A lot of mobs, you'll never find yourself waiting for re-spawns.
Skinning will be 300 so fast if you're not already 300.
Bad Points
World PvP, if you are on a PvP server. (Was not my case)
Long run to return to your grinding zone, that's why you need big bags and take nothing else other than what you REALLY NEED so you travel back less often.