If you give a parent the choice between having eight hours a day of freedom from their kids, or spending eight hours a day forcing their kids to learn to read and do math at home, no parent will chose the latter. It doesn't matter that homeschooling isn't really like that. Non-homeschoolers think it is. So the key is to reframe the choice.
Do not talk about how great homeschooling is. Because the benefits of homeschooling are foreign to most parents. For example, watching a child manage his own learning. That's amazing. But it's hard to believe it works unless you see it. Spending the whole day, every day as a family. It's a total joy. But no one would believe it if they haven't done it.
So instead, the best way to convince someone to try homeschooling is to focus on how terrible the current system for schooling children is. Mainstream media is not generally positive about homeschooling, but mainstream media loves to rip on how schools fail to work, so the evidence is easy to find.
Here is some positively irrefutable evidence about schools:
1. If all the educated people who say their kids are in a good school were actually in a good school then we wouldn't have a national problem with our schools.
2. To receive public funding, public schools must have test-based curricula. This is true for charter schools as well. They are public schools. They need public funding.
3. Test-based curricula is irrefutably ineffective and bad for kids. I'm not even providing a link, because it's so widely reported. However no one can think of a better way to run such a large and diverse public school system as the one we have in the US, so test-based curricula will persist for a long time.
4. Schools do not have enough money to cater to your kid. The student-teacher ratio is way too high for kids to get individualized attention. At best, kids get one or two hours of that a day. So why do they need to go to school for eight hours?
5. School no longer provides opportunities for socialization, because of the focus on test-taking. And the hours of homework after school do not allow for time for socializing after school. (Or family time, for that matter.)
It's pretty easy to see why school is terrible. And even though parents can't imagine they'd ever do a good job homeschooling, it's pretty easy to see that bad homeschooling is better than going to school. The kid has eight extra hours a day to figure out what to do with himself instead of being told what to do. How can this not be an improvement? Adult life is not about being told what to do. Why prepare a kid for that?
Parents tell themselves it can't be that bad because so many parents send their kids to public school. Parents want to stick their heads in the sand. But here's something to tell those parents: the truth is that the very rich do not send their kids to test-based schools. Those kids go to very expensive ($40,000 a year) private schools that function more like homeschool. And the fastest-growing group of parents taking their kids out of school are parents with a bachelor's degree and a household income in the range of $50,000 – $75,000.
So here's the logic that I think sells homeschooling most effectively:
School is terrible. Educated parents are taking their kids out. You need to take your kids out so they don't get left behind.