Petit Ami, this is a nice topic, thank you!
The image you posted can be explained BE NICE to anyone:
This is something that EVERYONE can do, smile or say hello to someone.
This will change someone's whole day, week, month, year or maybe even life.
Then they will be nicer to others, which just continue the cycle and won't even realize that you changed thousands of lives.
In one word LOVE each other.
I want to share these too, in topic "How to change the world".
1. Be Positive, let the negativity go and be free. This is simple but effective.
2. Listen to people, let them talk, learn about their lives, sometimes that's all someone needs.
3. Be a good Parent, teach your children about the world and how they can change it.
Teach them that the possibilities of life is limitless.
4. Be an inspiration, do something that people said you could never do. Take risk and succeed.
This will inspire others to do the same and continue the cycle.
5. Become a Teacher, become a teacher with the true ambitions of teaching children to succeed in a school life.
Not only teach them from books but also teach from life.
6. Dream and Do, dream of a better world then go out there and create it.
Dreams become reality with enough work and determination.