In the case of doing one mindful breath, the routine is to bring attention to the next breath (and, when possible, a gentle and intense attention). The reward is the sense of calmness that comes from the routine. All you need is the cue. Once you find the right cue, you will be able to form a habit loop and you will have at least a few breaths per day of meditation you can benefit from, which I promise you is far better than zero.
