To grow up in wow means to level up to 80. As in life so in wow, a player is given a choice of professions to choose from suitable for his character. There are 2 types of professions, primary and secondary.
Secondary professions
There are three secondary professions one can have and they are the same for everyone: cooking, fishing and first aid. Useful or not useful, it is for you to decide but it is advisable to have all since they will improve your character as you can make all the useful goods such as food and bandages and not be depended on others. After the release of Wrath of the Lich King expansion, having all professions will be a nice amount of achievements added to the list and will improve the status of your character and also get you nice rewards and titles.
Primary professions
Primary professions are also optional but most of the WoW players choose them straight away and level them up while they level their character. After getting professions to the max level you can still choose to take some other professions instead of the ones you got already, but be aware that you will lose all the recipes you obtained, and basically you will start from scratch. Primary professions determine your character in a way, help you earn gold and also can help you to level up depending on what you choose.
The choice of profession combinations is yours only but never the less let’s look at the best combinations advisable.
Mining/Blacksmithing
If you are a warrior the best solution for you could be mining/blacksmithing since blacksmithing uses mining products to make armors for plate users and melee weapons. It will help you level up faster if you can make the armor sets for yourself and not be depended on the drops. Mining is also a nice way to earn gold. By selling ores or bars on the AH aka Auction House one can make easy gold since a lot of other players will need it.
Mining/Jewelcrafting
Next good combination when it comes to mining would be definitely jewelcrafting, since ores are a need for the rings, necklaces and gems production. Jewelcrafting is also one of the most profitable professions in wow. A jewelcrafter can prospect the ores and get nice and valuable gems which he can sell on AH or make nice gems which are a must for any player as a gear improvement.
Mining/Engineering
Engineering is another profession which goes well with mining. An engineer will need various metal bars and items to make engineering products and level up the skill. With the engineering skill one can make bombs, trinkets, ammunition, parts of the armor, and various gadgets such as repair bots and jumper cables for resurrection and even mounts and flying vehicles. Engineering is definitely the most fun profession one can have but it is also very expensive and time taking to level up.
Skinning/Leatherworking
One of the fastest leveling skills is definitely skinning since there are lot of beasts for you to skin while you grind XP to level up. A best possible combination for skinning would be leatherworking since a leatherworker needs the leather to level up. Mail and leather users should definitely choose this combo for primary professions. While leveling a leatherworker can make armor and also armor kits which come as a nice gear improvement. He could also sell these on the AH as well as skins and earn some gold.
Tailoring/Enchanting
Another crafting profession is tailoring. Useful mostly to the casters and classes that wear cloth, tailoring is also very fast to level up since the cloth you need for leveling drops from most of the humanoid mobs you will grind. A tailor can make nice sets of clothes for healers and cloth dpsers. On higher levels he can also make threads that are a nice improvement to the gear and bags which of course come as a need to any player. Tailoring goes well with enchanting which together with engineering is definitely one of the most expensive professions one can have. By choosing enchanting as one of his primary professions a player gets an ability to disenchant uncommon, rare and epic items into valuable shards, crystals, dust and essences. These can be used to make useful and powerful enchants on the gear of yourself and others which could lead to making a lot of gold as well. Therefore tailoring goes well with enchanting since one can disenchant most of the tailor goodies he makes.
Herbalism/Alchemy
Another easy to level up profession is herbalism. Gathering herbs all across the map is easy while you level up. Herbs you can sell on the AH for nice amounts of gold or you can use them to level up your alchemy which comes as a perfect match to herbalism. An alchemist can make various potions, elixirs, flasks and transmutations usable throughout the leveling and also a must in the raids. At higher levels of alchemy a player can choose either to be an elixir, potion or a transmute master. Depending on which choice one makes, one will be able to make one transmute extra, more elixirs and more pots.
Herbalism/Inscription
Wrath of the Lich King expansion brought us also a new profession: inscription. Inscription is also a profession that goes nicely together with herbalism since a scribe will need herbs to make his products: the glyphs, vellums and cards. The glyphs are now a need for every player since they improve your abilities and skills. One can have three major and three minor glyphs on a character. A scribe will be able to create small decks of cards players can use at the Darkmoon Faire to get nice rewards. Another useful product are the vellums which an enchanter can use to cast any of their enchants upon and then give it to his alt character or just sell it to other players through the AH.
Recipes and Profession trainers
Most of the recipes you will need to level up your profession you can find at a profession trainer or purchase at certain vendors. Profession trainers are usually to be found in the capital cities as well as the vendors that sell recipes, even though some vendors could be found in smaller cities as well. Some recipes are a random drop from mobs that you kill on your way to level up and some drop in higher level instances and raids but those are likely to be rare or epic. Some are a rare drop and if you don’t feel like grinding for hours you can even obtain some recipes from the AH for a higher price of course.
