To-do lists are helpful, because they relieve your brain of the need to remember everything.
To effectively organize your time, you actually need TWO different to-do lists: a master list and a daily list. A master to-do list is an on-going, running memory list of everything you want to do someday. A daily to-do list is essentially your plan of what you truly intend to get done today. It's NOT an on-going list of everything you need to do, as in the master to-do list. A daily to-do list is the first thing you see in the morning and the last thing you see at night. It keeps you focused and on-target throughout the day.
When you think of something to-do, ask yourself when you're going to do it and record it on the appropriate list: the daily list for today and the master list if not.
Systematically review and move items from the master to the daily list, and you'll slowly make a dent in all those bigger projects.