I did it kind of slowly. First family study stopped. Then we would talk over the dinner table about things I found out about the borg. I wrote to the society when I could not get answers at home. Then I read the letters to the kids, and said, this is wrong, and used an encyclopedia to back up what I was saying. Then we talked about what they found wrong with meetings, a book, or something. The older ones were glad to leave.
I have my mom with me. She is an active witness, and goes out in service three times a week. So there are many nights she will start with what she learned at the meeting, and I have a counter to what she is saying. It's on going at all times.
When we stopped all together, the kids felt freedom, but then they started to feel like they were lacking something. So I started taking them to different churches, and learning other religions. #1 son doesn't want anything to do with religion, same with #2 son. #3 son questions everything, and if anyone tells him such and such is in the bible, he says prove it, give me scriptures to back it up, and then he will research it on his own. (he's 11, 12 next month) #4 son love going to a church with Sunday school, my daughter loves church with lots of kids to play with, and my youngest #5 son just turned 6, so he really doesn't care. He was 3 1/2 when we left.
Just give your kids the chance to find answers on their own. If there is a belief that is wrong that they are holding on to, ask them to show you why it is right. How, with the bible and/or a non biased source, to prove it. Use the same way to show them what it really means/says.
Teach them to think on their own. I did find, if you take away all the meetings, family study time, etc. away, you need to replace it with something. Sports, friends, clubs, something. That way they don't feel a void.
Hope I was of some help.