Below 3rd grade I sat with them at the kitchen table every single afternoon and patiently watched them and then checked their work.
Some teachers said they wanted the errors, what on earth is that about? I did not send them in with errors, we sat quietly and figured out what it was they didn't get. DS had some early trouble with multi-layer questions and DD had a hard time figuring out the core of some word problems but we got through that. I never understood the teachers position on this. THEY have 30 kids, I only had 2 so of course I would do a better job at weeding out the issues
By 3rd grade they were on a good autopilot plan. A and up I left them alone but anything lower and I was looking into why, not in a brute sort of way, more in a "lets see whats up" sort of way... which they didn't like much so they pushed against it. I didn't really help with homework other than to quiz them on vocabulary words. I did help with projects but my kids started to prefer independence so I gave it to them.
Basically, they only ever asked for help if they seriously needed it and would now rather do anything than have me tutor them because with me they get an ENTIRE lesson. Even now if they get a B they want no part of me tutoring and bring their grades back up on their own. DD6th has a 4.02 and DS7th a 3.84 (due to some homework issues in Spanish the 1st quarter, he now understands it is not optional

).
I think careful guidance when they are young molds them into good students later on