what are the qualities/parameters that a student look in a coaching institute before join?

It depends on to what level u can think perticularly physics. If u approach towards is logical then it will be better to go for preparation for neet. Otherwise now a days coaching institute has become a business. They will show u dreams with so many results n all. 

A better private teacher sometimes is more beneficial option. 

Mr. Shiv firstly u have to check whether the institute is giving the student correct time for their study.are the faculty assessing the scores of the student every week and counselling them. Are they rectifying the students faults and correcting them individually.... Bcoz every college more or less have a qualified lecturer with a very good teaching skills. But are they best at the above aspects. .that matters more

You will get an overall idea from any coaching centre . U cannot expect much from any centre . The main advantage is that u get study groups , u will get some pre tests , u can meet seniors and their experience . Make sure u should atleast have some basic idea before attending any centre . Because it is going to be only review sessions 

The teaching is to be done this way. when they teach you, you should be in a position to solve the problems yourself and answer the questions yourself. They have to give you the concept. In Physics they have to discuss the concept, discuss different applications, give notes and then solve different models. The teacher should be in a position to rectify the mistakes committed by him. The teacher should make the subject simple and give techniques of solving problems in a simple manner. Rangaji, Nagabhairava academy.