If a person took a look at the modern k-12 education system, they would assume the kids are learning important skills. Upon inspection of the modern education system, they would figure out kids aren't learning much at all.
Figure out exactly why you don't think the system is working out for you! Different people disagree with different things, and you might think the math and science system is absolutely bogus. Chances are you don't use trigonometry or calculus in your everyday career, so why would anybody reward a student simply for reading a book and taking a test on these subjects?
Step2
Ask the question, why doesn't anybody seem to care about the poor education system?
Step3
How effective would it be to start homeschooling your child now?
Step4
Ask the question, why isn't anybody questioning the ineffectiveness of teaching subjects that have been around for 100 years and hold no real value in the world today?
Step5
If a subject in school is basically worthless in your life, and you don't really feel like taking the class was useful in any way, why would it be logical to assume it would be useful to somebody else?
Step6
Realize how isolated your opinions probably are. Home schooled kids are a minority, and those who question the system are a minority also. Don't expect a lot of support of your opinions.
Step7
Question the system, don't attack the system. There is a fine line between you acting defensively- deciding to home school your child, and acting offensively- telling teachers how useless their teachings are, how appalled you are at behavior in the schools, etc.
Step8
Actually do something about it. If your own job takes up too much time for you to really worry about your child's meaningful education, do the best with what you have. Talk to your child after school about topics that are relevant to reality, not subjects only useful in school.
Step9
Be original.
Tips & Warnings
Don't attack the system, defend against it.
Exercise caution in what you say, because most people won't understand you (fact of life).
Don't be afraid!
Education reform is right around the corner, hopefully, be a part of it.