As a student pilot, what matters most to me are the instructor, the establishment, and the value the school places on me being a student of theirs.
Instructors need to be, or at least appear to be, genuinely interested in teaching (even if they are just waiting for the call from Q!!). Just dont let on guys if you are one of these!!! When you belittle your position as an instructor, just think what that does for a students confidence in or respect for you!
Instructors need to praise when appropriate, encourage as much as possible, discipline in a disciplined fashion, and yell only as a last resort.
Instructors need to be scrupulously disciplined pilots - no short cuts or acts of bravado, even tiny ones, ever!!
The establishment needs to be professionally managed and run, or be connected with, a highly credible workshop (ie good planes). This also means that they CLEARLY value their instructors and remunerate them accordingly.
And finally, students are a schools best selling agent. Look after students and value their potential as ambassadors (or as lambasters - your choice). You will secure student loyalty by running a highly credible organisation, but you might even find additional 'offerings' to further secure loyalty, eg prizes, awards, etc.