looking at other people's art is the most inspiring, which is a pretty generic answer i guess
i don't really feel like i've grown much as an artist in the last few years. looking at someone else's art or reading manga (i don't do that often...) and thinking "wow this is cool i need to create something like this" would have been my main drive to get better in the past but i don't feel that often anymore.
i could name specific artists but i won't because i'm shy (also there's a lot of them)

other than that i guess trying to make a specific emotion tangible and express it in art

Sun is me but worse pretty much. they aren't exactly like me in every way, but i gave them probably the most of my personality traits/experiences, taken to the extreme

difficult question, i was always making art in some way... i had a couple awakening moments where i was deciding to be more serious about it