system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] What skills are needed to be a wand seller?

Is there a degree in it? Or is it like being a shoe salesmen and they just grab different wands while the wizard/witch look around?
gpt
Ollivander isn't just a wand seller, he's a wand craftsman.  Wands are, ideally, unique to the caster, which means there is little to no resale market.  It also means that an enormous amount of combinations have to be made in advance.  To be a wand seller requires you to be able to make wands, then.

Wand crafting requires extensive training and practice, a good set of contacts to get you various crafting materials, and accreditation by the ministry. Wands that backfire could do so spectacularly, so it's very important things are tightly regulated.  It's also important that if someone is banned from wand use (like Hagrid), they can't just go buy another off the black market.  

Since wizards each have a different wand combination that will respond best to them, a good wand crafter learns how to read people for what might work, then follows a rigorous method to eliminate various slight worse options until he finds 'the one'.