Relax. The first thing you need to do as a parent is relax and take the public structure out of your home environment. For many parents, this is hard. While some structure is good, homeschooling is about letting the natural process of learning take place. The more you push your child, the more they will pull and the less motivated she will become.
Let him choose the curriculum. Do not let him have complete control over his studies, but allow him to be a major player in what he will be studying. If he enjoys what he is being taught, most of the work will be taken out of it for you. You will notice him becoming more willing to do schoolwork because to him, it's not a chore. It's something he enjoys doing.
Allow her to set the pace. If your child chooses to spend an entire day working on a science project, let her. Don't think twice about her not completing math, English or vocabulary. Guide her along the way of course, but take comfort in knowing that not only has she taken the initiative to devote time to a school project, but that she is still learning in the process.
Involve him in science and history fairs. These are great for homeschooled children for two reasons. First of all, there are fairs that are put on by many homeschooling support groups. This means that he will be in the company of other children who are homeschooled, children he can relate to and learn from. Second, these fairs are fun and allow for a lot of creativity. This is one asset you want to bring out in your homeschooled child. It is an asset that will help him get further in life than knowing square roots will.
Show your support for her interests. Do you remember when your child was a baby and took her first steps, discovering the open world around her? She would bring you anything and everything that excited her and it would make you smile because you saw the excitement on her face. Your reaction prompted her to go a litle further each time, learning more with every step she took. The same is true for homeschooling. When you support your child, when you smile at her new discovery and the pride she has in discovering it, it will motivate her to look and learn for more.