Most departments have advisors that can guide you through academic and career decisions.
Computer Science Mentors (CSM) run small-group tutoring sessions that follow the content schedule. Each section consists of 4-6 students and is led by a mentor who has taken the course before. CSM also holds review sessions and provides other resources throughout the semester. Sections open during the first couple weeks of school, keep an eye on Ed!
The Center for Access to Engineering Excellence (CAEE) provides free tutoring for CS 61B. The weekly schedule can be found on their website.
HKN provides drop-in tutoring throughout the semester in their Cory office. For their tutoring schedule, see the website.
CSUA is an undergraduate computer science student organization on campus. They hold tutoring sessions in their Soda office–the schedule can be found here.
UPE helps students navigate computer science at Berkeley. They provide career and academic office hours that you can sign up.