For moneymaking tips (i.e., professions that earn money), check my sig.
As has been mentioned, Alchemy is useful for making potions, which give stat boosts, as well as some selling well on the auction house. Engineering can be useful if you want things that might help in PvP. A lot of Engineering items require the user to have Engineering, however, so a lot of the things that can be made aren't really sellable to general consumers. Enchanting is a money sink at lower levels, but disenchanting items can bring in some moey if the mats are sold on the AH, and at higher enchanting levels, there is a demand for enchants (firey, crusader, etc).