It is very important to keep good records of your child's homeschooled years. Your records can be as simple as a daily journal or as elaborate as a purchased computer program or notebook system. If you are part of a support group or ISP, you probably will have set requirements and forms provided, but you will need to decide on how to keep track of your daily work to make reporting easier and more efficient.
The first step to setting up your record keeping system would be deciding what system you want to use. You might want to start by reading various Record Keeping Articles and by checking out commercial Homeschool Record Keeping Systems or Free Record Keeping Forms available on the web.
Record keeping methods:
Journal - This can be done by the teacher or by the student. Basically, it's keeping a log of what was done and what was learned. It is also a good place to record the memorable events that happen throughout your homeschooling years that would be forgotten otherwise. This is a great resource for reminiscing later on.
Daily planner - This is what I do: I lay out my plan (the assignments for the week) in a teachers planning book. I check them off as they are completed. I also jot down other educational things we did, like field trips, videos, projects, etc. in the planner. Quarterly, I make a summary of what was completed and an overview of what was covered in each subject.
Portfolios - Portfolios are a good system for child-led learning and unit studies. A portfolio is a collection of varied materials that show what the student has learned, experienced, and accomplished.
Purchased Record Keeping Systems - I've checked out a few of these. The Harris Homeschool Planner is good, but requires a lot of photocopying. I believe it was the first of its kind. Another homeschool organizer is the "Keepers At Home" Organizer. I like the freedom it provides to personalize the organizer, adding to it and subtracting from it as I see fit. I now have all my paperwork in one centralized spot.
Once you've made your choice on your record keeping method and obtained the necessary materials, be diligent in keeping it up. It is easier to record as you go than to play catch-up and try to remember what was done.