I would advise leveling against Tailor/Enchant. Even if you don't have to buy your mount, it's a huge gold sink, especially together. Another issue: with tailoring the profession will quickly outgrow your level, for example you are level 20, but in order to advance you would need to kill lvl 25 spiders for resources, so you are stuck until you get to that level and since the AH isn't developed to just buy the ingredients you won't be utilizing your profession. Enchanting is a huge gold sink because it's pure RNG. On fresh pservers, the go-to was Herbalism/Skinning, since you can vendor the Skins and Herbs are much easier to gather and level than mining, the nodes are often far away and in odd locations, where herbs are everywhere, and some herbs are basically useless other than leveling, meaning it's not as contested. You'll grind beast mobs while leveling so you'll naturally level it and it'll give you some extra gold for skill training (which is important for a Warlock) and also for your profession of choice. I wouldn't decide on your final profession as of yet, get a level 5 bank alt with enchanting to DE gear, and just go with herb/skinning, and at 60 decide what you want.