Notes

1) Is there anything I need to do?
Do you have homework? An important email to write? Some essentials to buy? Right then drop everything else and do it. If not move on to the next question.
2) What do you want to do?
If this is something bad, like go on reddit and kill time for an hour, then try to talk yourself out of it. Understand why it's a bad idea, ask instead....
3) What would your ideal self want to do?
This is the you, you want to be in a year. The you, you want to see in the mirror every morning, the you, you desperately want to become, but is just out of reach. What would they do, go for a run? Practise a new skill? Whatever it is DO IT. Though it is important to note that even the ideal version of yourself is human, and is allowed to want to watch a film, or play video games every once in a while.
I know this seems like a re-statement of pretty much every post on here: stop not doing it, start doing it. However I find asking myself these easy to answer questions makes it impossible for me to make up excuses, use faulty logic, and justifications, and talk myself out of doing something good.