- Review them regularly to keep them current. Pull out your lists whenever you have the time. Add new subtasks, check off done tasks, reorg lists if necessary. Keep your lists alive.
- Focus on the most valuable tasks first. One hint for what is important: Do the tasks you avoid most.
- Block chunks of time for uninterrupted work.
- Don‘t try to do too many tasks on one day. Don‘t overschedule.
It does not matter which tools you use. Emacs+Orgmode, Things3, OmniFocus (my fav), TaskPaper, etc. Just choose one tool and stick with it. Don‘t think the grass is greener on the other side. Don‘t switch systems constantly when your current system seems overwhelming. It will be overwhelming when you didn’t keep it current. Just review and reorg your system regularly and keep it alive.
Edit: Forgot the most important principle: Don’t think that you can accomplish all the things that are on your lists. In life you are constantly forced to decide what to pick up and what to give up. Constant trade-offs. Never think that all the things on your lists should be done either. The hardest part is to realize that on a meta level you can change structures that create tasks that shouldn’t be done at all, at least not by you. This meta analysis is the hardest part. Looking at all the commitments you silently make, the roles you accepted silently now generating tons of work you shouldn’t be doing.