Warlocks are one of the most powerful damage dealers in World of Warcraft. They can only wear cloth and since the Wrath of the Lich King their gear is spirit based even though they still need a lot of stamina and intellect.
Tailoring and Enchanting
Tailoring and Enchanting are usually paired professions when it comes to Warlocks. Since Locks wear cloth tailoring is proven to be very useful for them while leveling and even on higher levels since the gear they can make with is sufficient to be a good pre-raiding gear. By doing achievements they can obtain two epic cloak patterns from the tailoring trainer. A tailor Warlock can make embroidery for pants which can improve his stats, also could sell it to other players on the Auction House. If he/she would choose to buy it from other tailors it would cost some valuable mats and gold, while by being a tailor it only costs two Ethernium threads. Same goes for a few cloak improvements that tailors can make themselves. Another nice thing for Warlock tailors is that they can make bags, especially Abyssal Bag which is a 32 slot Soul bag where a Lock can put his/her Soul shards. The Enchanting on the other hand fits Locks perfect since they are dps casters and always need a lot of enchants to improve their performance in raids and instances and also in PVP. Disenchanting is also quite useful for any class and Warlocks are no exception. They could disenchant all the stuff and gear they don’t need or want into valuable items like shards, essences and dust. These items could be easily sold on the Auction House or used for enchants Locks themselves would need. While leveling Tailoring Enchanting is a profession that helps a lot. There are also few enchants that an Enchanter can put only on himself, like ring enchants with increased stats and spell power which would make a good Lock be even better.
Alchemy and Herbalism
Alchemy and Herbalism are always nice to have for any class especially casters and healers since they use a lot of potions. Locks can also make a lot of usable flasks and elixirs for themselves to boost their performance in raids and while playing instances or sell them on the Auction House for a lot of gold. With Herbalism since the WOTLK expansion comes also a nice healing buff called Life Blood which will heal you for 2000 over 5 seconds. It is nice for Locks since they use Life Tap.
Other
Other useful professions for Warlocks could be Jewelcrafting, Engineering and Inscription. Inscription is nice just because it is a useful profession, which will enable you to make useful Glyphs that you can use or just simply sell on the Auction House. With Engineering you will get to make nice mounts, gadgets and armor pieces such as Goggles, which are favored by the caster dps classes. Injectors for mana and healing potions are also useful since they will save up some space in your bags. Jewelcrafting is great since with it a Warlock can make nice rings, necklaces and valuable gems which are unique and soulbound to the wearer. If a Warlock would choose mining he/she would get a nice buff called Toughness which will increase your Stamina by 50, while with Skinning i.e. a Lock can get a buff called Master of Anatomy which will increase his/her critical strike rating by 32.
