What is the leveling path for First Aid in WoW?

First Aid is a secondary skill allowing you to make and use bandages for self-healing.

The cloth used to make bandages can be farmed from any Humanoid mobs, bought from the Auction House or found in chests. You first make bandages of a cloth type (Linen Bandages for instance) and can then learn the heavier variant (say, Heavy Linen Bandages). This pattern repeats until maximum skill level.

The needed cloth is as follows:

Linen Cloth > Wool Cloth > Silk Cloth > Mageweave Cloth > Runecloth > Netherweave Cloth > Frostweave