Mindful awareness in nature is a beautiful way to practice mindfulness.
Start outside in a place that has a variety of nature such as a park or your yard.
What do you see? Take in all that you see, expanding your sight on the big picture. Perhaps it's a large park with people, foliage, park equipment, a path, etc. Take it all in visually and don't miss anything. Little by little whittle down those sights to just a few things. Soon your attention and awareness will rest on one object such as a leaf. Bring your full awareness to that leaf and really enjoy it. Check out the color, the grooves, the bumps and veins.
Next, what do you hear? Listen to all the sounds - birds, people walking and talking, leaves rustling, etc. Take it all in and just listen (closing your eyes is helpful). Little by little focus your awareness and attention on one sound. Listen and bring awareness to how your body feels and reacts to the sound.
Next, what do you touch? What can you touch? Touch all there is to touch - metal, wood, sticks, leaves, a petal. When you are done, take one object and just hold it. See if you feel a slight vibration. Gently touch the object all over and take in everything you can about this one object.
Is there anything to taste where you are? If not, just pay attention to your mouth, gums, teeth, tongue, and lips. Notice that by just placing your attention in this area, your mouth, your saliva kicks in. Just rest awareness in your mouth and the sense of taste. Swallow.
Take a nice deep breath. Notice any and all smells and scents. Little by little hone in on one particular scent. Just keep breathing in the scent. Notice that your nose is used for breathing and smelling.
Honing your senses in nature will not only calm your brain and your body - you activate your sense of intuition. Yoi become more intune iwth your feelings and body sensations. You start to really pay atention to yourself in a good way. This is a beautiful way to practice being mindful and to awaken your senses.