It seemed they just liked having me sit with them. Maybe it gave them more confidence, I don't know. So I would sit with them on the couch helping when necessary. It depends on the child as to how much help they will need with essay writing. I have the children bring me their outlines, we go over them, they bring me their rough draught, we go over that, and then we go over the final copy.
Some children have no problem with writing, and some hate it.
Your reading aloud throughout their younger years will certainly help the situation. The first year your child does a science or history project he will need you to walk him through it. And that is the year you, the parent, will learn how to do a science or history project. Attend science and history fairs now when the children are young to get an idea of what to expect. Yes, they will need you at first, but as they get older, say 15, they will need you less and less.