Source:
The following list is a most-wanted list for trade skills (taking into account quality and quantity of the items you can sell). Save these items and make sure you sell them on weekends on the AH. They will fetch a nice price. One thing to note: Alliance players will find that Leather doesn’t sell very well while horde players can make a decent coin of selling skinning products.
Engineers/Smiths
1. Copper Bolt
2. Copper Tube
3 .Flask of Mojo
4. Gems
5. Pearls
Leatherworkers
1. Dragonscale
2. Leather
3. Leather Hide
4. Thick Murloc Scale
5. Deeprock Salt
6. Scorpid Scale
7. Turtle Scale
8. Ironfeather
Alchemists
1. Wildvine
2. Herbs
3. Sharp Claw
4. Delicate Feather
5. Small Flame Sack
6. Large Fang
7. Essences (Essence of Air, Water, ect)
Tailors
1. Spider Silk
2. Cloth (Silk, Mageweave, Wool)
3. Elemental (Water, Air, Fire, Earth)
4. Shadowsilk
5. Ironweb Silk