Xiam
What I like to do is pick from an archetype, then try to figure out what makes a person act like that, or subvert it. Either way I gotta go into "talking" to them or watching them in situations to see what they're like as a legitimate person, rather than just sort of "This is the stoic guy, this is the nerdy guy, this is the evil guy..."
This, sort of. Characters
fall into archetypes, but that doesn't mean they should be created as archetypes or that they should be limited to being archetypes.
In real life, archetypes are in the mind of the observer, and depend on the situation. One person might be their best friend's nerdy Q, their parents' naive but idealistic hero, and when things get bad, they might be someone else's mysterious saviour and another person's helpless damsel in distress.
Stories gain clarity from having archetypes be less fluid and less numerous per character, but that doesn't mean they have to be fixed. When you create stories, always consider how the characters perceive each other and how they would act in certain situations
as people rather than an archetypes. Let them fall into archetypes as needed, don't make them
be archetypes.
tl;dr: Archetypes are descriptive, they should not be prescriptive (except in meta works).