GTD.
I can't understand why GTD is not anymore trendy (at least in HN) once it is the most efficient system I ever used. Since I implemented it, my life changed and I not even thought of going back. If you ever get curious about GTD, besides reading the original book (Get Things Done by David Allen) you can have a look at my implementation: https://github.com/we-build-dreams/hamster-gtd , might be a good starting point.