A vocation is a bundle of three crafting professions with overlapping skills. Each vocation has a gathering profession, a production profession, and an extra profession. You have to be level 5 to learn vocations.

In case you are not quite satisfied with your crafting progress - I recommend you check out these LotRO guides. From making gold to hunters in Lord of the Rings Online they cover a ton of topics and come with an excellent leveling guide for all classes.

Armorer

The armorer profession can create a wide variety of armor for players, but they are especially keen at building heavy armor and shields. They are great miners and smelters, and can prepare the metals to their liking. They are also capable of crafting clothes and leather armor, however they will need to trade for the tanned hides that are required for such a creation. This is a great vocation to choose if you're going to be needing heavy armor as well as shields.

Armsman

If you're in need of a weapon, be assured an armsman can make it. Any class that relies upon the blade should strongly consider this vocation. The Armsmith is proficient and capable of all mining and smelting but will need to exchange with other players in order to make bows, spears, and other wood reliant items.

Explorer

Explorers are great at living off of what Middle Earth gives them. They are capable of crafting leather armor and clothing while gathering any resource they come across. The explorer vocation is a great choice for any class that wears light or medium armor or wants to gather all available resources in the land.

Historian

The Historian vocation is a unique one. They are granted access to the arts, which allows them to research ancient lore, scholarly works, and then use what they find to the advantage of their fellowship or kinship. They also have the more practical abilities such as cultivating land and forging ancient blades.

Tinker

A tinker is a master of jewelcrafting. A skilled tinker can create baubles of both beauty and use. A tinker can harvest the metals within Middle Earth and take the metals and stones and use them for his work. This trade requires long hours and fortunately a Tinker is capable of preparing hearty metals.

Woodsman

Woodsman are the premier bowyers in the land, and are capable of taking raw woods and crafting fine weapons from it. They can gather and treat the wood as they need. Their knowledge of plants and nature also makes them great at farming. Anyone who desires to make mighty bows should choose this vocation.

Yeoman

Yeomen till the soilds and prepare food with their natural skill. They are able to create cloth and leather amors though they will need the hides through trade. They are great preparers