Ask HN: How did you become more diligent?

I've found myself rushing to finish programming projects, essays and other things. I don't plan or think, I just do. I can code fast, so it creates results - but they're not long-term results. This always ends up in creating countless errors and mistakes. I'm looking to become more dilligent in my work. What can I do to practice this skill?

EDIT: Had to rename the title because I mispelt 'diligent' and didn't double check it. I found that hilarious.