This is a great video about the process:
Unlike the video above, I had dinosaur wall stickers from the Dollar Tree. My daughter picked them out and loved them for a few months. I myself was happy to see them go.
First pick off what you can gently with your hands. If the sticker rips or part of the backing stays on move to the next tips so that you don't damage the wall.
A hair dryer can soften the glue of the ones where the backing sticks or the sticker rips.
Before:
I was going to have an after but trust me when I say it was just a crappy photo of an empty wall and I lost that photo.
Drunk proof it: Use goo gone if you have any left over remnants.