A few years ago, the Educational Testing Service listed five primary factors that influence learning. Parents have a direct influence in all five areas. If children aren't in school, they can't learn. High attendance is almost always the sign of a good student. In study after study, children who watch lots of television do poorly in school.
Parents can monitor assigned reading and support that effort.
If your child's teacher isn't assigning reading, ask why not. Homes with books, magazines and newspapers produce readers and learners. Sometimes this can't be helped, but single parents can assure that school night routines are predictable and stable to allow time for school work and study. Be available to answer questions and help with homework. The first few weeks of school are crucial.