One of the things I used to do in first year was carry around the spare printing sheets. Everyone at UoN who has ever printed out something has had one. And I wasn't sure what to do with them (until I figured out the recycling process). However one of the habits I did develop was scribling ideas down on them. Writing down anything or even drawing on a piece of paper is 100% more effective then trying to type down ideas on a smartphone, tablet or laptop imo. Even if its just a phrase or a picture, these little things trigger of memorys in your mind which are great later.
In the spirit of not missplacing the piece of paper I was working with today, here is a scan:

(Click link to enlarge).