Yes, paper is so messy!
I've heard about the 3 things each day
I don't think I explained that properly, it's only 3 things at a time! So the rule is, you can't move onto anything in your inbox until there are a maximum of 2 things in your Today tray.
That way you remain focused without being all over the place, you can still do your 10 things, but you must do them methodically. I will talk about labelling next and that way you can prioritise what is most important to you.