You are able to have up to two professions. If you get bored with one of your professions, you can drop it for a new one. In doing this though, you lose all of your recipes. This means if you come back to the original profession, you still have to retrain all your recipes, and get the dropped recipes all over again. Professions are expensive, and in most cases will be a hole in your money bag long before it starts to fill it up. It is common practice to have two gathering skills until level 35 or higher before you switch to another profession. The reason most people wait until 35 is because at level 35 you can get your skill up to 300. At 300 you will start to make products that will sell for profit. People who wait until level 50+ are doing it so they can quickly level up the skill and farm whatever they cannot find, or don’t want to pay for, at the auction house.
Alchemy
Alchemy, the art making potions and elixirs that help the imburer out in many ways. With skill you can learn how to change base materials into other base materials, making iron into gold for example. This profession gives a shaman the ability to further augment his skills. The ability to make your own healing and mana potions can save you a lot of money, and earn you decent money. The ability to drink a potion and get stronger and/or faster is always a plus. The down side to Alchemy is most components are gotten through Herbalism. This means without Herbalism, this is a very spendy profession. Alchemy requires lot of different herbs, and at times, lots of an individual herb. Alchemy is a great profession to skill up while you level if you are the one harvesting all the herbs. Shamans should not pick this skill up at lower levels if they do not want to pick up Herbalism.

Blacksmithing
Blacksmithing is working metal bars into weapons and armor. This skill requires lots of ore, so if you are considering it, you should pair it with mining. This way you are able to save 75% of the costs by farming the materials yourself. Shamans can gain armor and weapons with Blacksmithing; weapons and armor that drop at lower level will always replace blacksmithed items until higher levels. Shamans should not take blacksmithing until they are above level 50 and are able to go through those lower levels of making stuff quickly. Once you are able to make some of the better weapons, it might be worth blacksmithing.
Blacksmithing at higher levels allows you to specialize in either Armorsmithing or Weaponsmithing. Weaponsmithing further specializes to Axesmithing, Hammersmithing, or Swordsmithing. By specializing, you are allowed to make and wield powerful weapons and armor. For this reason, Shamans should never specialize in Swordsmithing.
Enchanting
Enchanting is the ability to give extra abilities to items, and to take an item and remove all the enchantments on it to get regents to enchant something else. This is not a profession to take if you do not have some money laying around. If this is your first character, it may sound like enchanting is a good profession, but it is a total money sink until late in the game. This profession has no companion skill that works out to reduce the cost significantly. The best that people have come up with is partnering it with tailoring due to some tailoring items being cheap to create, and then you can disenchant them. You might want to consider partnering this with mining, or herbalism. You can sell what you harvest to offset the price of enchanting. The huge plus to enchanting is you can enchant your own rings, but no one else's. The enchants for rings are some powerful enchants.
Engineering
Engineering is the profession of making some really incredible items. They can make items that produce effects similar to most spells in game. The down side is that you have to be an engineer skill close to the level

to produce the item to use it. This means you will seldom be able to sell items as an engineer. Most engineers will simply make the item for themselves. One of the strongest profession that you can partner engineering with is mining. Mining will off set a large amount of your cost.
At 200 skill you are able to specialize in either goblin engineering or gnomish engineering. The differences are reliability vs brute force. Gnomish engineering makes some versatile and more reliable items. Goblin engineering makes some big explosives and also items that have a more extreme result than the normal or gnomish version. The Goblin versions also are more likely to explode or backfire.
Herbalism
Herbalism is the ability to gather the various herbs that grow throughout the world of Azeroth and in Outlands. Herbalism is pretty straight forward: it gathers different herbs. When you activate it, it will send up yellow dots on your mini map when you get close to one. You can gather herbs with minimal requirements for how low your skill can be and you can still harvest the herb. If you gather herbs as you level, you should seldom run into an herb you can not harvest. You can then sell these herbs on the AH for decent money. Once you start harvesting in Outlands you will find sometimes you will get a buff from harvesting a plant. Just another bonus to harvesting herbs.
Jewel Crafting
Jewel Crafting makes different gems, rings, amulets, and a couple other miscellaneous things. This craft can be very expensive due to the fact that the materials needed are used by other professions. The best profession that jewel crafting can be paired with has to be mining. This gives you the ability to use the ores, and you can also prospect the ore to have a chance at getting a gem. This profession is expensive until you get higher in level. With this profession you also have to make sure you don't flood the market with your products. Only put up a few at a time for sale.
Leather Working

Leather working is the ability to make skins, scales, and other animal parts into armor. The use of leather makes this profession best paired with skinning. Skinning will save you a lot of money. Leather working is a decent profession for a

shaman to pick up. They can make armor for themselves, and as they get higher in leather working skill they can make mail armor. This also allows you to make armor kits that further your armor class.
Later on, you can specialize in Dragon scale, Elemental, or Tribal armor. Tribal armor is great for Elemental or Restoration shamans who want the hit points. Elemental armor is great for Enhancement shamans.
Mining
Mining works very similar to Herbalism. You find mining nodes and harvest them. When harvesting mining nodes you can find ore, stones, and gems. Mining products are used with a lot of other professions. This means you will have a good buyer's market for your products. If you are not going to use the products of mining, sell them off and make some decent money.
Skinning
Skinning is exactly what it sounds like. You collect hides, leather, and scales. Leather products are gathered from beasts primarily, once in a while you will find other mobs that you can skin. The products that you collect should be used for your own professions, or sold. The market for skinning products is not nearly as good as mining or alchemy, but you should be able to sell your products.
Tailoring
Tailoring is making products with cloth. Tailoring for shamans is seldom done due to the fact that shamans normally wear heavier armor. The reason some shamans pick up tailoring though, is because of the ability to make bags. While Horde, leather making can make a single bag. Tailors can make a variety of bags. The largest bag can be made by a high-end tailor. There is always a market for bags. The higher end bags can bring in decent amounts of money.
At high skill you are able to specialize in a specific type of cloth. Primal Mooncloth, Shadoweave, or Spellfire are your choices. All three of these cloths can be made by any type of tailor, but if you specialize you can make two times the amount. If a shaman is going to do tailoring, he should specialize in Primal Mooncloth, this being the type that makes the largest bags, and it can make some good healing gear for a restoration shaman.

Secondary Professions
These professions are in the game that everyone can get and they do not count towards your two profession limit. I recommend that shamans keep all of these skills up because they will make your life easier if you have them skilled up as you level.
Cooking
Cooking: you take raw and other ingredients and add them together to create a better product. Foods when you get higher can give you a “well feed” buff. This a buff that stacks with other buffs and is just an added benefit. The most common is increased stamina and spirit. This means more hit points and faster regeneration of both health and mana. This is cheap to level up as long as you gather the materials yourself.
First Aid
This skill allows you to turn the different cloths that drop from humanoid NPCs into bandages that you can use to heal yourself. You can also make some anti-poisons, but the anti-poisons don't keep pace though. I know that you are probably thinking “I can heal, so what do I need bandages for?” The great thing is you don't use mana to use bandages. You can save it for later on. Now, if you are full mana and you are not going to fight for a while, go ahead and use your healing spell. But, if you are raiding and in a brief pause before the next pull, you can heal yourself and others without any mana by using bandages.
Fishing