Jewelcrafting - World of Warcraft Profession Powerleveling Guide
Jewelcrafting is the new profession that came with the release of The Burning Crusade. With Jewelcrafting as one of your trades, you will be able to create rings, necklaces, cut gems for socketable items and make shiny trinkets.
Because jewelry and gems are used by everyone, jewelcrafting doesn't particularly benefit any specific class.
At end levels of Jewelcrafting you will be required to throw a lot of money at gem cutting recipes that you might never make the money back from - and to become diverse and have lots of different cuts you'll need lots of gold. On top of that most of the gem cuts aren't that profitable. Maybe this will change once people stop needing the skillups from the cuts, as right now some gems actually sell for more uncut than cut. Of course there are some cuts that are more profitable than others, which I will get into later on. I think the trick is to only invest in a couple of useful recipes and then make your money back before buying new ones.
Jewelcrafting and Other Trades
The main components for Jewelcrafting are gems and bars. As you can get these from Mining, it is the best trade to take up with Jewelcrafting. If you're a miner you also have the choice between prospecting the ore you mine (in hope of finding more gems) or turning them into bars that are used in creating jewelry.
Enchanting doesn't need any gathering trade so can be a good combination with Jewelcrafting. Also it means that when you advertise your cuts you can advertise enchants as well and thus get more customers - so a good combination for players that like selling their abilities rather than selling items.
Another option for a second trade is Tailoring as it doesn't rely on any other trade either. Tailoring and Jewelcrafting could be a very nice combination on a caster character (mage, warlock or priest).