[tripzilch]

Okay, this is one very simple thing, and the only one I can personally speak of having at least a qualitative and even sort-of quantitative positive effect.

Someone once gave me a little hand-made note book that said "Each day I write down 3 things I am grateful for'. So I started doing that.

I didn't want to write down obvious things like being grateful for having limbs, eyesight or such, mainly because you can write down the same every day. So at first I found it kind of hard to come up with three genuine novel things to be grateful about. But after a while (3 weeks or so?) I found that I had to stop myself from writing down more than eight things :-) (that is eight new things each day)

I mean, it's not a full journal, and the effect is relatively small (or is it?). But it's also something very easy to pick up, and you can actually evaluate its effectiveness somewhat by paying attention to the effect I described above. Which is what you asked about :) All in all, I suppose refutable claim is that if you do this simple exercise you will find it becomes easier to have positive thoughts and be more grateful about life.