Well – I am not that a Leica Expert that I can give you the perfect hacks for this iconic camera…but I can give you my findings from two years of shooting…
First – never wind the film if you are not certain you are going to take another shot. The reason is that you will most probably get a shot from inside your bag – the shutter button has no lock. The exposure meter will also be activated – which will drain the battery.
To be sure to not drain the battery – set the time settings wheel to OFF or B. The camera will still work without the battery – but not the exposure meter.
If you use glasses – and shoot 35mm or wider – see if you can find a M6 with 0.58 magnification. That give you the chanse of actually seeing the frame lines.
I find the M6TTL more logic as the arrows in the exposure meter point toward the direction you should turn the wheels to get the correct exposure. The classic M6 has a smaller time settings wheel – and it is to be turned against the arrows in the meter to correct the exposure.
Try using the same film speed over time to learn how to judge the light. Today we are spoiled with nice exposure meters in modern cameras. The one in the M6 is nothing like modern meters.
Last – don’t get irritated on the fact that a film Leica is a little bit more complicated to reload with a new film. Use the time to slow down, take a breath and think about how lucky you are to be able to shoot with a Leica. 🙂