Making a mural for a child's room doesn't have to be intimidating. You don't need fancy tools or buckets of acrylic, oil or house paint. All you need is a little audacity, some tape, Elmer's glue, a sharpie and a kids watercolor set, and some paper - either construction colored or water color.
I realized last year that you can decorate windows with drawings on cut out construction paper and just dab the back with a glue stick in one or two points, press it on the glass and it will stick for a year if you want. To clean it off - just use hot soapy water.
I did the same to a little girls room recently, only I used tape to stick the cut outs to the wall.
"Thank you for turning my room into the monterey bay aquarium Holly!" she said the next time I saw her.
"Oh sure thing!" I responded. I'm glad she liked it because I did it one night when i couldn't sleep after mistakenly eating a Crunchie at 1am. WHEN will I learn about chocolate and sleeping?
SO now there are these fish on the wall and the potential for us all to add to them with more drawings if we want.
It's such a simple idea, and it can be as temporary as you want, but judging by my window experiments - it could stay up for a long time too.