First create awareness with easier things. You are walking, you are taking a bath, you feel thirsty, you feel hungry - start with these things, all very ordinary things. You were just going to speak something to someone: Stop! Even in the middle of a sentence. You were going to relate a story you have related a thousand times, and you have bored everyone with it. You were again starting, "Once there was a king..." Stop! Start with easy things more easy things.
There is a fly on your head and you were just going to send it away with your hand: Stop! Let the fly be there, let your hand remain stopped. Do it with easy things so that you have the feeling, the feel of stopping with awareness. Then move to complex things.