I totally agree with the previous posts.
Without first learning proper form, you'll drive yourself nuts trying to tune arrows (and you'll spend a lot of $$$) cutting shafts to chase accuracy that you will not see on a consistent basis unless you develop proper form.
Its tempting to ask then, "Well how in the heck am I supposed to figure out proper form if my arrows are not tuned?"
The answer is - shoot arrows that have the least wobble in flight like Bisch suggested. Do that for a Looong time.
My draw length is 28". There were times in my early learning where I was drawing 29.5" (over expanding) as I'm only 5'10".
You have got to obtain the 'feel' of proper form and a consistent shot cycle. The fundamentals of form are absolute - you gotta have the proper alignment of angles or you will not get good flight or accuracy. Each individual has their own minor tweaks that vary from shooter to shooter, but they all have proper gross form alignment of angles, and a consistent shot process. Its the same as with golf. Good golfers all have th fundamentals of proper form, with minor differences individually.
There is no fast way to accuracy in order his art. It takes thousands of shots over time, and you will tweak your tecnique many times over until you finds what feels good for you.
You'll reach a point where you can consistently shoot that 'least wobbly" arrow into groups at 20 yards that are the size of your open hand. If you can do that, (consistently) then your form and technique is pretty good.
Now if you start tuning (spine, arrow length, head weight, brace height, etc), you'll easily see the difference between a properly tuned arrow and your "least wobbly" arrow.
I have what I believe are nearly perfectly tuned arrows. When I'm in the zone - they fly like bullets and hit my mark (where I look) dead on with scary consistency and accuracy. However, those same arrows will occassionally 'wag' their tail end to the target. When I see that, I know its me (my form), and not my arrows.
In other words - even with properly tuned arrows I STILL get bad arrow flight every now and then, but it is because I'm doing something wrong in my form and I can usually get back on track within a dozen shots or less.
There is constant practice and refining in this art.
I know this was a long post, but the key to this is - Just Shoot a LOT, every day, over, and over, and over. You will evetually stumble upon the proper form with your individual tweaks that works for you.
When you do - you can tune arrows to a point where you are ridiculously accurate. That kind of accuracy is so darn addictive that you'll have to shoot your bow at least every other day just to enjoy the release of pleasure endorphins in your brain.
People who have reached this ZEN know what I mean by the pleasure endorphins!