What advice would you give someone to make them stop cutting themselves?

You can't make someone stop cutting.

Don't you think it's time to move on? To bigger things? Start cutting others.

I've tried, and tried, with adults and children. Nothing I've said has helped. I did outdo someone, to show them how it affects others. I think that made it worse.

Find out the source of the anger. They are still hiding something that bothers them and motivates the self harm and low self esteem.

Make then change the city. Get new friends those who don't his/her story.

Cutting makes your skin look ugly, and it's not worth it

I'd ask them if they've figured out what blood looks like yet.

What Svan said.

See a doctor, or a psychiatrist. Reminds me of a friend I had who had borderline. There's medication for that to repress that need.

I understand that you must be going through a tough time. Now, how about we sit and talk for a while?

I'd get them to join a religion that forbids self mutilation.

Something like "Stop cutting yourself!!!!"

Put the knife down?