How does one even get a job or learn new traits? Who can't I marry?

Okay, so I have a few questions.
How would I get a job or supervise over a building/shop? Do I have to befriend the shopkeepers? Do I have to do things like for the blacksmith, build sickles and sell them 100 times?

Is learning new traits, tasting things? Or is it just getting those notes around the place?

How can I tell who is eligible for marriage? Like I'm a female and want to try to marry twig but don't know if I even can?

I don't know if these questions are okay to even be asked about but I hope its okay. I don't mind if only one question is answerable.
So far in a slump. -w-)

Shop ownership is coming next update. You can't currently date or marry (upcoming too).
You won't be able to marry Masters.

Thanks so much for answering.