Ideally find an older instructor that has been at it for awile and is not there just to build time. IMHO these schools that are pilot mills are turning out very marginal pilots. Add to the fact that a lot of the instructors are products of the same school just perpetuates the problem. I would much rather see you find a good stick and rudder guy with an older well maintained airplane. The new generation is all enamored with new airplanes with glass cockpits and only learn how to drive an airplane not fly it. Also most pilots will tell you to go right in with an instrument rating right after you finish your PPL. Do yourself a favor and do a good aerobatic course then spend a few hundred hours flying VFR. This will get you your tailwheel endorsement and also make you a cut above the average pilot. Unfortunatly insurance is the big roadblock for learning in a taildragger. Insurance on a RV6 isn't too bad even for a low time taiwheel pilot and goes down substantually at around the 100 hour mark. Don
I agree whole heartedly with a lot of this comment. I finished my PPL in August last year (after more hours than I care to admit). In spite of my pragmatic nature AND all my research, I still ended up with an instructor I HATED. Not personally, but I think he was bad at being an instructor. It was just chance that he was standing there on day-one and got signed on as my secondary. Then, the day after my solo, my primary left to take a job. I gritted my teeth and kept this other guy until the end, but I really hated the fact that I felt like I was not getting what I was paying for. Yet, at that point, my options were limited.
Fast forward to today. I am now logging hours and building my experience (and filling in all the skills I think I should have honed a little more as a student). But I am also getting tail wheel training from a fulltime instructor, with thousands of hours and a lot of it in the bush, in a J3 Cub, and the experience is so much better than my PPL training. I feel like I am correcting a lot of bad habits I acquired early on. I attribute this to the quality of the trainer, not necessarily the type of training (though some might argue otherwise).
A lot of this might sound good in theory to you at this point, but if you take nothing away from this, look for an experienced instructor. Somebody that instructs because they like to teach, not because they are logging hours for a new career. This is going to be much easier said than done, but well worth the effort if you can accomplish it. If you end up at a school with a lot of instructors logging time for themselves, you are likely going to be taught to pass the required tests, but not how to be a good pilot. Maybe this is the goal for a lot of places. Afterall, the PPL might be argued to be a ticket to go and start learning for yourself. But I would argure that just because you are trying to cross a particular finish line, doesn't mean you should settled for lower quality help along the way. You are going to be paying virtually the same money regardless of who sits in the other seat.
One other thing I will mention. Different parts of the country price the service differently. Not much you can do about. But you will also see that some schools only have a newer, glass panel type of fleet. They are going to charge you more in relative terms for that type of plane. And that is going to add up. My school had several 172P models from the late 70's to the early 80's. They were $30-$40 cheaper than the R and S models they also had in the flightline. I trained in the P models because I didn't want to pay more per hour for a plane that had a newer airframe or fancier avionics. Just something else to consider when you look around. You might be able to find a school with an older Cherokee or Warrior, maybe even a C152, versus a G1000 Skyhawk SP fleet.
Good luck. Getting my PPL was one of the top handful of accomplishments in my life, and well worth the effort.