Y is for You.
I'd like to say that I deliberately left the hardest lesson till almost last, but it was just how the letters fell. To be honest, when I was sketching out how an A-Z might look I chose something completely different for Y. But that other word didn't feel right, which is why this entry is late - I've been fighting against writing it as it didn't seem worth writing about. Maybe W should have been for "wait", as sometimes your brain wants to cogitate some more on a project before throwing the right answer your way.
Anywhow, we're not here to talk about me; let's talk about you...
That's right, you are the most important part of your system for getting things done. Not just in the hippy sense that it's all about you achieving your goals and making your life better, but in a much tougher and more difficult-to-master sense too.
For the system to really work then you need to get to grips with how you work. You need to spot the ways that you undermine your own best intentions; notice the natural rhythms to your work; pick up on what you find hard or what you can breeze through...
Then you'll be able to mould your system so that it works with you rather than against you: put measures in place so that you can't distract yourself; recognise when it's that time of day when your productivity is low (and either use techniques to help you inch through it, or get away from the work for a while and come back to it later); acknowledge that you're working on stuff that you find difficult, and forgive yourself that it's taking longer than it should.
So, in summary, try to cultivate an awareness of your behaviour and actions, but remember that if it wasn't for you, nothing would get done.