I found the best way to level up is to make tons of worthless (White) items. These will not sell on the AH. However, they usually cost fewer materials than green items of a comparable level, thus making you lose less (as random world green drops are usually a tiny bit better than tailored greens of the same level. And they also allow more stat customization than tailored goods).
Also, try to ride out one type of cloth for as long as you can. Case in point, I rode to 225 on only silk; didn't touch mageweave, which is 60 silver more expensive per stack on the AH (and rising) and it gives you less bolts per stack.
A good thing to keep in mind: each rank of cloth gives you fewer bolts per stack. Linen gives you 10; wool, 6; silk, 5; mageweave, 4; and runecloth, 3. You can go a lot further for a lot cheaper with lower-tiered cloth.
There is currently a glitch with Tailoring in that all recipes are orange colored (they say you always get a skill-up). This is not true, unfortunately. Try to keep track of when you get a new recipe (the Tailoring skill required for it). After about 15 levels, it will be yellow; after 25-30, it'll be green; and 15-20 more and it'll be grey. Sticking with a white recipe that costs fewer ingrediants for 20-25 levels is a safe bet.
I recommend a gathering profession to go with Tailoring, because you'll be out of a lot of money since you can't sell your cloth. Cloth is a major commodity, and since you won't get money from it, you're going to be very poor :-P. Lots of people say Enchanting is good, but if you aren't selling green world drops nor cloth, you'll be broke by the time you need a mount. That being said, if you are a Warlock, go for it ^_^ Priests and Mages might want to hold off on Enchanting until higher levels, when greens are easy to farm.
By the way, if you're a Mage (Forst-mage specced). I hear you can make a ton of silk by AoE Blizzarding several enemies at a time in the Wetlands. They drop 1-2 pieces of silk each and are (I think) in their mid-twenties. Just an idea to keep in mind. In my experience, here's the best (Alliance) places to get cloth:
Linen (level 1-10): Gnolls in Elwynn forest, the south-western part. There's a ton, and they drop a good amount.
Wool (11-20/25): The Deadmines. The elites drop up to 4 wool at a time. They also drop a lot of linen. In the Wetlands, closest to Loch Modan, there's a small camp of low 20s Orcs. I believe they'll drop wool for you.
Silk (18-35): The undead in Duskwood. There are a ton, and they drop a ton. Also, the trolls in Arathi Highlands (Witherbark) drop decent amounts and you get Wildhammer Reputation. As I said, Dragonmaw Orcs in the Wetlands drop some, or so I hear.
Mageweave (35-50): Harder. Dropped infrequently, or in small amounts by enemies in this level range. I know a great place is Azshara, there are ghosts who drop up to 3 pieces at a time (and silver as well). They're level 45-47, though.
Runecloth: The Scourge in the Plaguelands, hands down the best place to go. You'll probably grind up your last few levels around here anyway. You'll get a ton. The Scourge's lowest enemies are 50, and go up to 60+ elites. If you're 50+ equip the Argent Dawn's trinket to collect Scourgestones while you fight ^_^
Hope that helped :-D