Big bags.
Every little detail helps you make more gold in warcraft. First thing you will need is large bags. Buy the 18 slot (Imbued Netherweave Bag) or 20 slot (Frostweave Bag) bags from the auction house. This way you will have enough slots to pick up everything you loot in your grind or leveling run. When you are leveling or grinding, leave all your other gear on the bank. All y ou need is your DPS set, your heartstone, a stack of food and water. Everything else just takes up space.

 

Auto Loot.
We want to loot as fast as possible, this is why you should set your loot options to auto loot.  This will save you a lot of time in the long run. this is also a great option to turn on when you are fishing.  

Turn on auto loot in the interface control options

Turn on auto loot in the interface control options

Sell Junk Addon
I’ve used this addon for years because it saves a lot of time searching your bags for grey junk items.  SellJunk sells all junk to the vendors. This includes all grey items and user specified items, that can be added to list of exceptions. It can either sell these items automatically at each vendor or you can do it manually by clicking “Sell Junk” button on each vendor’s frame. You can also see how much gold you made from selling the trash. It can also destroy all junk instead of selling it, if you’re far from vendors. However you are reading this because you are interested in gold. And selling greys is extremely lucrative .
Download the SellJunk addon (at curse gaming).