I feel that the best way to build rapport with students is to relate to them. Nobody wants to have a pile of tuition assignments to do on top of school assignments. Therefore it is very important to be flexible and to take into account the students' timetable and curriculum.
As for parents, I feel that a good way to build rapport will be to be honest to them. When updating parents on student's current progress, we should always be honest and also let parents know what they can do best in order to help their child.
Keeping Up with Curriculum
To keep up with the curriculum, a good way will be to obtain latest assessment books. Keeping up with the current affairs is also another way.
As a Good Tutor
I think the basic qualities of a good tutor is to be responsible. In any case that a tutor cannot make it for the assignment last minute, he or she should be responsible enough to inform the tutee or parents.
Also, a good tutor should not encourage spoon-feeding towards students and should make concepts understandable and not just let students memorise.