Hmm. I should do the pen and small paper notebook thing. I had tried to make it a habit once, but maybe I just need to try with a few sheets of paper in my wallet.

Notes on the phone - maybe I need to reduce the number of clicks to be able to capture them faster (Google Keep widget maybe?)

I've tried using few pieces of paper tied by strong paperclip.

Doesn't work for me - I've lost some notes that way. For me notebook as temporary information storage is better.

Good to know! I'll stick to a tiny diary. Will make a habit out of it. :)

What do you think of supporting email/sms to enter items into a master queue?

I add a entry in my Google calendar from either my phone or my home PC. Next day at work, I will see it on my phone.

how do you manage items you don't get to? and how useful to you would data of task completion by type, time, etc be?

The calendar entry is just a reminder, not an appointment. By the way, I also use 'Keep' than allow sharing notes between PC and phone.