In the introduction to his book Teach Your Own, John Holt lays out 7 rules which he suggests are fairly obvious to anyone who's good at sharing their knowledge with others:
(1) to help people learn something, you must first understand what they already know
(2) showing people how to do something is better than telling them, and letting them do it themselves is best of all
(3) you mustn't tell or show too much at once, since people digest new ideas slowly and must feel secure with new skills or knowledge before they are ready for more
(4) you must give people as much time as they want and need to absorb what you have shown or told them
(5) instead of testing their understanding with questions you must let them show how much or little they understand by the questions they ask you
(6) you must not get impatient or angry when people don't understand
(7) scaring people only blocks learning
I think these are excellent guidelines, and thought I'd comment on how they've worked for us as homeschoolers.
Regarding #2, letting them do it themselves is best of all, let me say that this is harder than it sounds. Take early math, stuff like 5 + 7 or 6 x 9: I had my own rules and mnemonics for problems like these. If you want to add 7 + 5 you first add 7 + 3 (easy, that's 10) and then you stick on the remaining 2 to make 12. When your kid can't quite remember that one, you really want to tell them how you do it, and sure, that might be useful. But your kid might be destined to think of 7 + 5 as the same as 6 + 6 (therefore 12) because 7 is one more and 5 is one less (my daughter's method). Or they might be destined to figure it as 5 + 5 = 10 and then stick on the extra 2 (my mom's method). Whichever method they discover, they'll remember it because they figured it out. It will be the path of least resistance for their particular cluster of neurons in which addition facts are stored. And so, their own method will be the best method for them and it's probably best if you just keep your mouth shut. But this is incredibly hard to do, especially when feeling under pressure because "we must be behind in math," something I have periodically decided all throughout my kids' homeschooling years.
#6, you must not get impatient, is also harder than it sounds because often the only way to avoid impatience is to abandon the topic altogether for a while (say half a year or a year). When my daughter could sound out "cat" letter by letter, and yet would not string them together to say "cat" as one syllable, that was a very frustrating time (and it went on for 2 years). If you can say "k...a...t" then why can't you say cat? But I didn't want to make her hate reading and I didn't want to hate homeschooling. So we just stopped doing reading altogether. I did it on faith, after talking to other homeschool moms. My daughter was 6 at the time. She taught herself to read at 7 1/2, spent several months reading only comic strips and non-fiction science books from the library, and then launched into fiction with a fervor which has made it hard to keep her in books. She's re-reading some Rick Riordan at the moment because she quickly exhausted all her Christmas books (and her brother's) and we've been sick and haven't gotten to the library.
Both #2 and #6 take faith. That's a huge part of homeschooling. When you start out and you're reading some of the homeschooling books or homeschooling-friendly books (e.g. Alfie Kohn's books), and you're feeling pretty geeked about homeschooling, that's great-- but stop and ask yourself: Do you really believe it? (You probably do, but stop and ponder it.) Do you really believe that kids learn best at their own pace? That curiosity and a desire to learn generally results in learning? That it's okay if they're not learning on the school schedule? That everyone learns differently? You'd probably say "yes," but in my experience you have to really buy it deep down in order to have the faith to follow John Holt's suggestions. I don't always have that faith, and it leads to some bad parenting / teaching moments.
A few things that I find helpful to keep in mind:
Schools usually figure that in a given hour of school, there are about 10 minutes of effective instruction. We know this because when children are too ill to attend school, districts send out a tutor to visit them at home for 1 hour out of the day (10 minutes x 6 classes).
School curricula look impressive because they're written to look impressive. It doesn't mean that a) they'll actually make it to the end of the curriculum; b) that nothing will be skipped; c) that it will look as impressive in practice as it sounds like on paper; d) that your kid will be interested or attentive; e) that your kid will retain the information even if they do get an A on the test.
I talked to a mom whose 13-year-old daughter attended public schools through last year, but has been homeschooled this year. This mom asked her daughter whether she felt she was learning as much material at home as she had been last year in school. Her daughter replied that it was hard to say, because while she was in school, "I got really good at forgetting everything on the test by a couple of days later."
And lastly: in my own experience, the things I remember best and use the most are the things I learned outside of school. There was something very different about learning it of my own volition, in my own way, at my own speed, and to meet my own real needs (or for my own enjoyment).
We've been doing this for 8 years, but I still have to work at keeping the faith sometimes. I love John Holt's rules, I just hope I can do a better job of trusting in them.