Tutoring must be tailored to individual student's need.
I have been volunteering as a school tutor for 2 years now and my approach has always been like that. When I tutor someone, I first try to understand how good he/she is with simple test. Then I plan the tutoring sessions according to such need.
However, there is a certain "pattern" in my tutoring. I first begin the tutoring session with explanation of the contents based on syllabus. Formulas must be thoroughly explained and the tutee must understand how and where to apply the formulas. Secondly, I give some exercise questions. I make sure the questions are of a great variety so that the tutee is well-exposed to different situations.
Lastly, I adopt past paper session. This is perhaps the most important session as the tutee applies his/her knowledge of the topic and understands how good she/he is. However, focus must be given to exposing tutee to different past papers rather than more of them. Simply repeating the same contents over and over again never yields effective results.
So tutoring is simply: understanding -> reinforcing -> testing -> evaluating. In addition, tutor must ensure that she/he gives some useful tips in regards to studying routine, time manamagent, stress management and etc. throughout the tutoring session. It is these tips that give tutee extra edge.
I personally reckon tutor also has a responsibility to act as a mentor.