There's one persuasion technique that has been consistently shown to work in almost any situation. It's very practical, can be used by anyone and doesn't involve a carrot or a stick. In the US it's known as the ‘But you are free’ technique. In the UK we'd probably say, ‘It's up to you’ or ‘You are free to choose’.
Why does it work so well? Because it tags onto the end of your request a phrase that reaffirms people's freedom to choose. You're not forcing them to do something, you're simply asking them politely and then reminding them that they've got a choice.
When my sons were young I would use this technique to stop them swinging from a dangerous tree, trying to jump ...