This is probably the most important advice about drawing I can give and it is the cornerstone of how I draw.
To demonstrate this I’ll use a pencil and paper and an object to draw like a desk lamp or something.

So, as an example, I draw an outline of the object to the best of my ability on one half of the page.
Then I draw the object again on the other half of the paper, only this time before drawing anything I pause…

I look at the object and close my eyes then mentally outline the object in roughly the same place in my imagination.

I don’t cheat or lie, if I imagine it incorrectly I’ll mentally rub it out and imagine it again until I am practically tracing the object in my imagination. If any angle is wrong I change it, if any line is too short or too long, I adjust it. etc. It doesn’t matter if I can’t visualise the object well, I’ll just ‘sort of’ do it and my brain understands.

I open my eyes as much as I want during this process to refresh my memory then I’ll alternate between open and closed as I begin to outline the object on the other half of the page.

I now expect to see an improvement in my drawing, at least in the proportions, as I have now learned how to draw the object in my head first before drawing it on paper!

In other words, the head leads the hand and works best when it knows what to do.