I started up the First Aid Skill, so that in the upper levels, it will be easier to heal my self. Plus, it's much faster than regular food. Here is a guide that I'll be going by when leveling it. 

       This is a First Aid Guide for 1-450 (updated for patch 3.2). The focus of this guide is to level your First Aid up as efficiently as possible, and since First Aid is relatively very easy to level up, this will be simple. This guide will also provide you with a general idea of how much cloth you will need to have in order to get your skill up; however, the amounts listed here are just guidelines and the number of cloth pieces you use will probably vary.

        While First Aid doesn't cost much to level up it also doesn't make much gold for you. If you need help coming up with new ways to make gold then look at this Gold Guide.

        The first step to beginning First Aid is to go to the nearest First Aid Trainer and train First Aid. Once you have trained First Aid you are ready to begin collecting cloth to create Linen Bandages (a formula you received by training First Aid). If you are going to fight humanoids for Linen Cloth keep in mind that humanoids which are levels 5-15 have the highest percentage chance of dropping it for you. A complete list of the optimal level humanoids to fight to get cloth can be found here. Otherwise, you can simply buy your cloth on the auction house.

Projected Skill	Item	Amount to Craft	Components
1-40	Linen Bandage	45	45 Linen Cloth
40-80	Heavy Linen Bandage	55	110 Linen Cloth
80-115	Wool Bandage	50	50 Wool Cloth
115-150	Heavy Wool Bandage	50	100 Wool Cloth
150-180	Silk Bandage	40	40 Silk Cloth
180-210	Heavy Silk Bandage	35	70 Silk Cloth
210-240	Mageweave Bandage	40	40 Mageweave Cloth
240-260	Heavy Mageweave Bandage	22	44 Mageweave Cloth
260-290	Runecloth Bandage	42	42 Runecloth
290-300	Heavy Runecloth Bandage	10	20 Runecloth
300-330	Netherweave Bandage	30	30 Netherweave Cloth
330-350	Heavy Netherweave Bandage	20	40 Netherweave Cloth
350-400	Frostweave Bandage	65	65 Frostweave Cloth
400-450	Heavy Frostweave Bandage	97	194 Frostweave Cloth

       In the following table you will find a list of bandages and levels at which they turn “green.” It is here simply for you additional information in case you decide not to follow the guide above.

Item	Level it Turns Green
Linen Bandage	45
Heavy Linen Bandage	75
Wool Bandage	115
Heavy Wool Bandage	150
Silk Bandage	180
Heavy Silk Bandage	210
Mageweave Bandage	240
Heavy Mageweave Bandage	270
Runecloth Bandage	290
Heavy Runecloth Bandage	320
Nethweave Bandage	347
Heavy Netherweave Bandage	367
Frostweave Bandage	392
Heavy Frostweave Bandage	430

How to Level First Aid after Reaching Skill Level 300

Alliance: If you are Alliance you may train from Burko in the Temple of Telhamat (Hellfire Peninsula) or a Grand Master First Aid Trainer. To find Burko look at the main entrance of the temple, run up two sets of stairs and turn left, follow the road to a little building and you will see Burko.
Horde: If you are Horde you may train from Aresella in Falcon Watch (Hellfire Peninsula) or a Grand Master First Aid Trainer.

How to Level First Aid after Reaching Skill Level 375

To be able to level past 375 you'll have to visit a Grand Master First Aid Trainer, the chart below will
 show you where to find one:

Grand Master First Aid Trainer	Location	Horde or Alliance
Anchorite Yazmina	Valgarde, Howling Fjord	Alliance
Brynna Wilson	Valiance Keep, Borean Tundra	Alliance
Olisarra the Kind	Dalaran	Alliance/Horde
Nurse Applewood	Warsong Hold, Borean Tundra	Horde
Sally Tompkins	Vengeance Landing, Howling Fjord	Horde

Where to get "Manual: Heavy Frostweave Bandage":

The trainer will teach you Grand Master First Aid and Frostweave Bandage; however, you will need to get a manual to learn how to make Heavy Frostweave Bandages. Getting this pattern is very easy. First off you must have Grand Master First Aid trained and have a First Aid skill of at least 390 to be able to see and loot the pattern. The pattern is a world drop but seems to have the best drop rate in either Normal or Heroic Instances and Zul'Drak. Don't think you'll be grinding for hours to get this pattern, it drops very quickly once you have both requirements for the drop fulfilled.