Assess your child's character strengths and weaknesses. You as the parent should know your child better than anyone else and should sit down and list the areas where your child needs help. Is she a self-starter or does she need someone to get her up every morning? Is he easily distracted or is he able to focus on a task until it is finished?
Assess your child's academic strengths and weaknesses. Standardized achievement test scores are helpful here as they can identify academic areas which need improvement. Past school grades are also indicators of strong and weak subject areas. Using both of these tools will help you to know which academic areas to focus on.
Identify your child's learning style. Most people learn by watching, by hearing and by doing in some combination, but most people lean strongly toward one of those. You can spend money on expensive tests to determine this, but you can usually identify the learning style by noticing how your child shows or tells you something. If they are a visual learner they will probably say "Look at this!" If they are auditory they will probably say "Listen to this!" If they are kinesthetic they will probably say "Watch me do this!" While this is not a very scientific method, you can put this together with your own parental knowledge of your child and make a pretty good guess.
Build a curriculum that fits your child's needs as identified in the steps above. While many vendors offer complete packages which include all the subjects for a given grade, it is usually better to go the eclectic route, pulling in the best math, the best grammar and the best of the other subjects. Children are not "one size fits all" and they need a variety of learning materials for the best education. If your child is ready for it, pre-algebra is good for math.
Determine your schedule and stick to it as closely as possible. Look at the number of math lessons in your chosen book and spread them out over the school year. For instance, if there are 140 math lessons and 180 days in your school year, you should do about one lesson a day. This leaves days for field trips, tests, sick days and other school interruptions. For science, you may just need to divide the number of pages in the book by 160 and do the resulting number of pages each day. The important thing is to stick as closely as possible with your schedule or you will be "doing school" all the way through June.
Require your child to learn as much as possible on her own before coming to you for help. You may even want to push her to keep trying to figure it out on her own for awhile. When she sticks with it and figures out a math problem or a science lab, it will be hard to contain the excitement. This practice will help your child learn to learn, which will pay off nicely in the high school years. It will also help him to become more of a self-starter, which is an invaluable trait for high school, college and the rest of his life.