California schools have standards http://www.cde.ca.gov/be/st/ss/index.asp that students need to learn at each grade level. Ask for them. Read them.  Learn about what your child is expected to learn and know in each subject.

Ask your child what he/she is learning and if he/she has homework. Do this every day for elementary and middle school students.

Set a time and place in your home for your student to do homework.

If your child is falling behind, talk to him/her about what is hard. Many schools have after school homework help. Talk to the teacher or someone at the school office to find out how to get help for your student. By helping your child overcome difficulties in school, you show your student that you care about his/her school work and that you will help him/her be successful.

When your child starts seventh grade, learn about the requirements for high school graduation and what is needed to meet the prerequisites for the state university system.  The right class choices can help students be prepared for college.  Of all the important ways you can help your child, showing you care and getting him/her help to succeed in school work is the best way to help the student graduate from high school and go to college.