Don鈥檛 use a Todo list. Use a Done list. Do it first then write about it later.
If you need to remember what to do, start by doing the first step immediately, even if it鈥檚 just making an empty document with a title. The existence of the partially done task is better than a task
I think we have enough todo lists and habit tracking apps now. Build something else. If I can achieve 90% of your app's functionality using windows notepad, don't build it.