Complex sentence: By the time Davis began taking his side-hobby as a drug dealer as a career, he was a freshman at Ronald E. McNair High School, where he got good grades and was considered popular among his peers.
Split into simpler sentences: By the time Davis began taking his side-hobby as a drug dealer as a career, he was a freshman at Ronald E. McNair High School. Davis was a student who got good grades and was considered popular among his peers.