The biggest difference is that successful schools teach in ways that are directly the opposite from what is fashionable in the public schools in general. Successful schools spend their time on the three R's, they teach reading with phonics, they memorize multiplication tables, and -- above all -- they have discipline, so that a few disruptive students are not able to prevent all the others from being educated.
Despite the self-serving claim from the teachers unions that successful schools for minorities skim the cream from the public schools, often these successful charter schools or other private schools admit students on the basis of a lottery, so that those they take in are no better than those they don't.
The students they admit are just a lot better after they have been educated where education is the top priority.
One of the schools I researched years ago that impressed me the most -- in fact, moved me to the verge of tears -- was a ghetto school in a run-down building, located in a neighborhood that caused a friend to say that I was "brave" -- he probably meant foolhardy -- to park a car on the street there.
The children in that school scored above the national average on tests. In their classrooms, they spoke the king's English, behaved like little ladies and gentlemen, and made thoughtful answers to the questions they were asked. Yet these kids came from poor homes, often broken homes, and many were on welfare.
You can't buy that quality of education for any amount of money. It has to be created by people who have their priorities straight. Don't tell me it can't be done when I have seen it done with my own eyes.