I use my grandfather's method: Legal pad to-do lists.
Each day he would write the list of the day's tasks on the top page, then use the rest of the page for notes throughout the day. The next morning, he would copy unfinished items to the next page, then tear off the top page and discard it.
Rinse and repeat.
He called this legal pad "his computer" and if it could work for him, it could work for me. I've been using this method since college (either with an actual legal pad or using a simple text file) with great success. Just the simple tactile act of writing to-do items down keeps them top-of-mind all day.
After trying many methods (as seems everyone on this thread has), this is what I do too.
I think that software for people who do this might approach a solutions by starting with a basic text-editor/word-processor and adding some features to it, slowly. Remember that you are making a list.
Apple mail notes/tasks gets that general idea right but it has so few features that it's not all that useful. Working with email (eg turning an email into a task) is important, so mail clients are in the best position to produce this stuff.
Each day he would write the list of the day's tasks on the top page, then use the rest of the page for notes throughout the day. The next morning, he would copy unfinished items to the next page, then tear off the top page and discard it.
Rinse and repeat.
He called this legal pad "his computer" and if it could work for him, it could work for me. I've been using this method since college (either with an actual legal pad or using a simple text file) with great success. Just the simple tactile act of writing to-do items down keeps them top-of-mind all day.