Wherever a character lives there are so many things to do and there’s a living to be made off of the work doing it. Some skills require lots of training and a knack for it, others the character just needs to be willing and able to do something that most others would not do. Some professions pay a lot some pay next to nothing at all. Some are forced into their vocation, others fall into it, a few get to choose it or change to something different. A character’s trade may be held in high esteem where you are while found distasteful or illegal a few cities away.
There are apprenticeships, guilds, overseers and mentors. In the world of Valyr a character may or may not get to choose but there is always something about the first skill that will be a part of the character. In the end, it’s what you do!.