Several times during the course of the day, take a few seconds to check in with your ‘mental TARDIS’.
Are you in the here and now, observing? Or are you some time in the past, remembering? Or off in some possible future, imagining? Maybe you are somewhere that has no sense of time about it at all, dreaming? Do not try to analyse or judge it. Just note which it is: observing, remembering, imagining, dreaming.
Is the experience pleasant, unpleasant or neutral for you? If you have time, explore that sensation of pleasantness or unpleasantness, as in the Sensory Awareness reflection, but do not worry if time is short; just note the experience and move on.