Depending on what is the easiest. Around sunday I write down a few to do's in my calendar. On a working day I'll decide what the 3 most important things are for me that day, if I've something planned with friends or would like to go exercising that will be one of those things too. I don't necessarily write them down. Sometimes you allready have in mind what your focus will be on the day before. Otherwise, like on a free day I'll think what I would like to achieve as part of my morning routine. At the end of the day (or the next day) I write down in short what I did and sometimes how I feel.