Congratulations on starting the flight training. I started mine just down the road from you 3 years ago this week, finished up in February of last year. Here are a few of my observations along the way, most of which have been mentioned by others already.
1. It seems that the #1 lesson in flight training is learning how to wait. Waiting for Alberta weather to cooperate is a big one. There seem to be many more opportunities to delay than to proceed. You wait for planes, instructors, examiners, other students, vehicles blocking hangar doors, dispatchers for fuel, gaps in heavy circuit traffic, winds to shift and a whole lot more. I had extra delays in getting my medical and also had to wait out a shoulder dislocation (lost balance pulling myself up to dip the tank on the school C172). With this in mind, you may want to get your medical done sooner rather than later. If there is any risk that getting a medical is going to be anything but easy, it is much better to learn that early.
2. Fly as much as you can, I found gaps of 2-3 weeks between flights really slowed retention of what I was learning. I find currency to be a big challenge while building. I'm trying to fly once a week now as I build, pushing for 100 hrs PIC before my plane is ready. I am getting 3-4 hours a month now and that really helps with retention. While training, I really only felt I was learning/progressing when I was getting lessons once a week or more.
3. Avoid stressful flights, your flying really suffers when you're tense and stress makes for a lousy learning environment. One of the best opportunities for distractions, at least in my experience, are communication issues. Noisy radios are a serious irritant, I've scrubbed flights and lessons because of it. It is much better to cut a lesson short or cancel it than it is to have one that is only going to stress you out. Marginal weather falls under this as well (unless it falls under my next point). For the comms, buying a headset and getting away from the school's dubious pool of headsets was a big help - although I just replaced the first cheap headset I bought because it was failing and I was getting nothing but noise with a full throttle. I just picked up a pair of CrazedPilot CP-1ANR headsets and they are wonderful. They'll also work great in my plane.
4. Don't measure your progress against anyone else. When it's all said and done and you have your fancy license booklet, it doesn't really matter how many hours it took to solo, how much you went over the minimum requirements or how much extra you spent on your instructor. All that matters is that YOU learn to fly the plane correctly in all imaginable situations. Really, the more unusual situations you can run into with an instructor in the right seat (rather than on your own with no support), the better off you'll be. One of the most terrifying realisations that I've had is turning final at night with a gusty direct crosswind, a recent active runway change and the potential for wake turbulence from the B1900 I just had to divert for and trying to remember how to do a crosswind landing and knowing that the only person that was going to get the plane down safely was me. At that moment I would have gladly gone back in time and paid for an hour of the instructor's time to do that landing with a safety net next to me.
5. Take the time to enjoy the experience. It's a pretty special thing you're learning to do and there are many moments that are great to experience.
6. Yep, trim=good. So is using your rudder to stay coordinated (or not when you need that). Also, keeping the push/pull of the throttle the right way around is much easier on your instructor. That one was probably just my own mental block.
I see now, reading back to your original question that I probably didn't answer much of it. So you can read this as a list of things I wish I had known when I started. I'm still a rookie so I'm sure the list will grow. Really, flying is probably the best learning opportunity I've ever had.
Enjoy the adventure.
