Here's an exercise you can use to begin to notice your breath or to find it again if it's become cloudy in your awareness. There are infinite ways to do this. As you change your attention use your mind to continue to notice, resisting any urge to judge or compliment. You may notice other sensations and movements that are not described here. The realm of the breath is infinite. For this exercise give value to all things you notice without qualifying them.
Sit somewhere quiet and in a comfortable position with your spine easily in neutral.
Allow your body and mind to settle.
Find a comfortable soft focus with your vision. Tune into your mind's eye.
Let your breath move normally. You don't need to control it or change it. Breathe here for several rounds until you feel like you can really place your mind solely on your breath. It may want to wander into daydream, sleep or to do lists- just notice those tendencies and stay with your breath.
For the next rounds of breathing place your attention on your nostrils. Notice the sensation of your breath as wind moving past your nostrils in both directions. Notice the temperature of your breath. Feel how the breath tells you the shape of your nostrils and breathing passageways.
Return to just watching your breath from the bird's eye view of your mind, letting your mind remain empty except for noticing.
For a few rounds place your attention on your rib cage. Feel the expansion of your rib cage on the in breath. Take in all the directions your ribs can expand placing your attention on the front, sides, back, top and bottom with no rush. Watch how the size and shape of your torso changes as you breath. Then place your attention on your out breath. Feel the ribs draw closer to the center line of your body and the sternum drop away from your chin.
Return to just watching your breath from the bird's eye view of your mind, letting your mind remain empty except for noticing.
For the following rounds place your attention on your abdomen, the great space below your bell shaped rib cage housing all your viscera. Let your attention expand from your bottom ribs to your hip crests and pubic bone in the front. Watch what happens on the in breath and where your breath travels in your torso below your lungs. Stay with that for a moment. Let your attention travel to the back of your torso all the way from your lowest rib to your sitz bones -- feel the directions your torso expands on the in breath, where pressure might increase or decrease and what sensations caused by the in breath draw your attention.
Then place your minds eye on your solar plexus right in the center of your torso. Still without changing anything, notice how your breath travels through your center, supports your center, changes the shape of your center and is also affected by your center.
Sit quietly for a few more breaths with your minds eye just resting on the continuous tempo of your breathing.