I run a Trello board along the lines of Getting Things Done, i.e., everything I have to do goes into this board. It starts with "incoming" list, which can also be filled from email. Every morning I look at what is there in the "incoming" list and these tasks move on to "today", "this week" or "later" lists. Also, tasks from those lists go back into "today" if needed. When I'm done with a task it moves to a "Done" list, which gets emptied automatically every night. Additionally, I have a "waiting on" list for things out of my control. That is about it. This system is free, I can success it from anywhere, and it is motivating to drag stuff over.