The biggest help I did for my kids was to put homework squarely on their shoulders from a very young age. I was completely fed up with it in early elementary school. I had my kids in 3 after school sports and I worked full time. From the time I picked them up after school we went straight to whichever sport they were in and then home for dinner and by that time they were basically done for the day. There was no time for long bouts of homework nor was I going to fight with them over stupid busy work which they already knew how to do. All it did was make the rest of evenings miserable, they were getting very overtired and I was having none of it. My boys had to be in bed very early on school nights. Normally at that age they were in bed no later than 8:30 at the latest and I wasnt keeping them up later to do homework.
I went to the school and point blank told them they werent doing homework anymore. I didnt give a horses behind what they wanted to do about it grade wise either. Their classroom grades and test scores showed they knew the material so whatever. Oddly enough by the time Jamie got to middle school and high school, he started doing his homework on his own because he needed to do it to go over what was learned in class. I never had to tell him or force the issue. He just took on the subject himself. If he didnt understand something he would ask me for help or ask me to help him get into tutoring at the school. So by not pushing the issue and making it a huge fight, he learned that when something was important he needed to do it.