Ask HN: How to think of an idea for a cool project?

I have tried many times to come up with an idea to start a personal project. However, every time I come up with something either a similar or better implementation exists or the amount of time, effort and skills involved huge. It would be great for me if you can share some thoughts/experiences of how you come up with and idea for projects. Reasons why I wan't to do this: - It's fun - Will me a better programmer (I think) - Looks good on my resume