Level with a pet if you can because it will help keep you safe. If your pet is tanking all of the damage from the enemies you’re fighting, you won’t have to. The other reason is that pets are easier and cheaper to heal than you are. If you don’t have a pet, make sure you know how to use your defensive abilities. You can’t level quickly if you are dying all the time.
An important aspect when selling transmog on the AH is that it often takes some time to sell. Therefore you will make more gold the more diverse your portfolio of items is. If you only farm one tier of gear. Lets say for example gear in the 60-80 bracket. You will be limiting yourself as the demand won’t be there and you will end up with too many items. You will end up with many of the same items for things that aren’t in demand but might sell occasionally.This means that spreading out your farming across all tiers is best, as you will get fewer of each item but more different items to meet the actual demand.
If you are not the leader of a high tier guild, do not worry because you can still make gold off of raids. This is the newly emerging GDKP runs that a respectable raider can put together (See why it is so important to keep a good reputation on your main toon?). Respectable raiders often take a few of their friends they can trust that have a lot of gear and bring random people along through the raid. Whenever a boss is killed, the items are auctioned for whatever base price you establish or more. You then split the money with your friends to keep everyone trying and happy, while you become richer without doing anything out of the ordinary. This seems like a perfect idea that can not fail, but it still has its risks. The tips below will help maximize the potential of the GDKP run.
Materials ('mats') - items that get used in professions. This is driven more by use than by source; for example, copper is very easy to mine, but it is widely in demand, and you can often find bargains in copper, bargains you can profit from. Contrarily, some very scarce mats may have low demand, may only be used in one mediocre recipe, and may not sell.
I made some route changes to the Horde levels 43-44 sections.  I have swapped 44 Dustwallow Marsh with 44 Desolace (the entire sections). This allowed me to do Deadmire (at lvl 43 instead of 38) and then go stop at TB to turn in Deadmire + The Black Shield at the same time, then fly quickly to do the Desolace stuff.  Doing 44 Desolace is now mandatory because I think its faster with the new routes. This will also make the level 53 grind much shorter.  I think these were great changes.
1. Signing Guild Charters-Many people will journey to Orgrimmar or Stormwind to get their new guild charters signed by alts and bank toons. This is where you can strike quick and fast without any risk of losing the investment! This is the greatest type of opportunity for any entrepreneur. I have seen anywhere from 5-20g per signature on these charters. This beats the heck out of earning that first hundred gold through mining copper or an alternative profession method. If you are on late at night, that is often times when the most people are looking to get this service done. Supply them with your signature!
Tiragarde Sound and Stormsong Valley are both fairly similar zones, but Stormsong is a little longer, meaning that you might not even have to finish it to hit 120. Tiragarde also comes with a bit of a warning. There are plenty of side quests to do in the zone after you finish the story quests. Don’t do them. It’s not worth the time or the experience you’ll get.