Dailies: With the introduction of daily quests in patch 2.1 of the Burning Crusade, players were able to do repeatable quests for a fixed amount of gold each day. These quests have been expanded upon tremendously in Wrath of the Lich King. With a plethora of 'dailies' around the entire continent, players should have no trouble completing the maximum allowed 25 daily quests each day. At level 80, the average compensation for a daily quest is 13 gold; that's 325 gold a day if you complete 25 quests a day. These quests range from extremely easy and quick to moderately difficult and time consuming. Knocking out 25 dailies in 2 hrs is not at all out of the realm of possibility.

Professions: Making wow gold from your professions used to be the easiest way to make money prior to the introduction of daily quests, and for some, it still is the easiest. The challenge in this method lies in the difficulty of maximizing your profession skill and learning the rare recipes/plans so you can make big-selling items. The most common and easiest professions to make money in are Blacksmithing and Jewelcrafting. If you mine the minerals yourself, you can make a boatload from blacksmithing, as most of the recipes that will bring you in gold are available from your trainer. You can make a lot by selling titansteed weapons. This takes time though as finding titanium and smelting it into titansteed takes a while. Jewelcrfting can be a good choice. While you will have to make an initial investment to buy the recipes, the trick with this is to buy saronite ore form the Auction House and prospect it to get blue uncut gems and turn them into cut gems.

Grinding: This isn't for the faint of heart. Grinding, or farming, is killing regular mobs over and over again, looting what they drop and selling it on either the auction house or to a vendor. Unless you're lucky enough to get an epic item from killing a mob, this method will take a long time. But if you find it peaceful to go into a killing machine mode, this may be the best method for you.

Raiding: If you are in a legit raiding guild and you have most laces on farm status then you are going to make money. If you are just beginning as a raiding guild, however you are going to lose money. So this is completely dependent on if you are in a raiding guild and how easy you are clearing places.

Your best bet is to go with dailies. Professions can be hit or miss, depending on how much things sell for on your server, how easy/hard it is to find the reagents needed to make your items, and competition. Grinding will almost always take quite a long time to successfully save quite some from, and raiding can either be a huge success or a disaster in terms of bringing in gold. With dailies, you always know you can get a certain amount, and that amount is dependent only on you and how many quests you want to complete.