Wonderful slogan English is by your side

Don't draw! (on the wall, things on the wall can be added later according to the situation. )

Don't throw peels about.

No littering! (in foreign countries, you can simply say this, don't be scared by such things as "peel")

Please?Keep?Off?the?Grass?

Please don't trample on the lawn! (that is, stay away from the lawn! )

Please don't hesitate.

Don't destroy trees! (Foreign countries say, don't cut down trees indiscriminately)

It can't be wrong, don't worry.