How to take tution so that children could get high marks?

Answer 1

Sorry but I don't really undserstand the question.
"Tuition" is usually thought of as the amount of money you pay to a school for instruction. Perhaps you are asking about sending your children to private schools? I might be able to help more if you clarified your question...
Here in Japan there are special schools called "juku" which specialize in helping children pass tests that allow them to enter high-level schools.