​Affirmations are a useful tool to affect the trajectory of individual, personal development. By repeating out loud these positive words, the human mind can absorb the images, while imagining oneself not just becoming that but already being that. The self-talk inside one's head becomes positive and supportive.
Affirmations are always stated in positive terms, clearly articulating what behavior or quality to aspire to. Avoid using negative terms such as "never," "not," "stop," and "no" that may describe current behaviors to change. Start with one to three at a time.  Children may come up with their own as well. 
In my own experience, affirmations are very powerful!

AFFIRMATIONS
For Young Children and Others
Rev. August, 2018
 
I am strong and healthy.
I am a very good problem solver.
I am creative and have a lot of good ideas.
I keep trying when something is hard to do.
I face challenges with confidence.
I am getting smarter every day.
I am a good listener.
I have self-control.
I am a very good friend and very kind.
I learn from my mistakes.
I have choices and I make good choices.
I am happy.
I am brave even when I am scared.
I take care of myself.
I take care of nature because I know that I am part of nature.
 
AFFIRMATIONS, NATURE BASED
I take care of nature because I know that I am part of nature.
I am a good helper in the garden.
I am gentle when holding living creatures.
I am kind to all living creatures.
I walk around growing plants.
I am respectful of all plants and animals.
I follow the rules of the garden.
I pick up trash in the garden when I see it.