Voters under 40. White Women. Asians + Hispanics. Try to hold as much Black support as possible. Gays and Lesbians. Jewish voters.
She will probably do better than Obama among all these groups except Blacks and voters under 40. Still more than enough to win.
Wouldn't Hillary do worse among Hispanics? This likely has nothing Obama, but rather that Hillary probably won't face an opponent that advocate "self-deportation".
Also, African American might not be such a problem. After all, they did turnout in an odd year for a some dude McAuliffe.