Here's something I know a lot of parents with school-age children struggle with. What's the line between "helping" a child with their homework versus out-and-out doing it for them? At what point is too much help a problem? How would one know if they're starting to do the assignment for the child rather than providing guidance/assistance?
As a former math tutor to children in middle and high school, and now a father, I can tell you a way to avoid the problem completely. Gain an understanding of the concept yourself, and make an equivalent problem that uses the same steps/ideas. Walk them through step by step, explaining as you go. One or two examples like that should be enough for them to understand well enough to do other work on their own.
This takes a bit more work, but it really teaches them. Most kids will be all too happy to just copy you or follow your lead and never gain an understanding of the work. The best way to avoid it is to do absolutely none of their actual work.
There's a pretty clear line between "doing the work" and "helping someone understand how to do the work".
One technique is to ask the child to explain to you how a problem would be tackled; or if the child is baffled to ask the child if the problem can be split into smaller bits, and how one of those smaller bits would be tackled. That makes them do some work, and explaining something always seems to make things clear for the person doing the explaining.
Sometimes children just don't get something. I have never been able to do "long division", and it's nice if a parent can recognise that and ask the teacher if there are other techniques.
Finally, having a source of appropriate research websites available would be handy. Here's a UK website from the British Broadcasting Corporation with a lot of useful information - some media might not work outside the UK.
The way I have looked at it is if I am writing anything down I am doing it, I will coach my son into trying to work out the answer giving him more hints if he is not getting it. Sometimes it will take a bit with certain subjects, but usually we work it out. Writing is harder, and we do Chinese characters for his Chinese School, so for that if I must write I will do it on a separate piece of paper so no matter what he will still need to write it on his own.
You know you're doing the problem FOR them when they continue to ask you to 'do the next step(s) for me' - and you do them, repeatedly - the same 'type' of problem. It becomes obvious that they haven't learned the concept behind the homework.
I worked with my daughter to help her understand how to start working on a problem, most notably word problems for math & science. Basically, I taught her how to get from point A to point B. I would never just 'do' the problem and give it to her, because that's not HELPING her.
In my schooldays, math caused me the biggest troubles. My father's help was fantastic, but he never solved any problems for me.
Instead, my father taught me the principles, or helped me understand the ideas, on which the problems were based. He never wrote anything down on paper, but we had a blackboard that he used for graphs and formulas.
For writing assignments, the hardest bit was getting started, and keeping going for long enough at a time. My father would then sit near my desk and repeatedly ordered me to Write! he'd keep doing that until I had something substantial that I could finish on my own.
I'm going to get a whiteboard for my kids. And a comfy chair by their desk.
What do you see homework as for? What are you teaching them by helping them with their homework?
If homework is to help them learn, you can teach them about understanding and working through a problem, about team work, and that they can do the homework themselves. (With a little help in the right direction)
What you don't want to teach them is that can avoid work by getting others to do it, that delaying work until they don't have enough time to do it means they won't have to do it, that they can't do it for themselves.