The right school
A couple of points to add. Check and ask around what kind of fuel the school is using. It has been a trend for flying schools to do a mix of AVgas / MOgas you would want to stay away those that mix it up or even worse us pure Mogas.
another helpful tip is to ask and check around the number of incidents / accidents the school has had. This will give you a very good insight on how well the institution is ran.