I also try to have high-level items for the day so that I know what I'm focusing on. Anything that I need to do but can't do today I put on a list for the next day.
It seems to be working out alright for me.
I currently just throw it all into OneNote, although it's not the greatest for dealing with lists the way I use it, but the freeform writing surface and search it provides makes up for it.
Forgetting is my number one problem right now. I also noticed there's some kind of unconscious filtering going on in your mind. Even if you write down the tasks your mind prioritizes them on its own.
What I wish list software had was a way to push those less important tasks in the background.
Sometimes I'll hit HN if I'm waiting for something to finish, and if I was in the middle of something complex I've needed to write down what I was doing, even if it was only for literally a minute.
Also, when incrementally learning something it can help. Writing down in your own words how something works can help you if you only have small chunks of time to learn something.
The key is not just to break things down and to create tiny, regular actions. It's also to start. Most of us like to talk and talk and not actually do anything at all.
This procrastination and hyperbolic discounting means that we often go for the quick fix rather than the ongoing journey to success. Starting and overcoming our own psychology is often the hardest part.
http://en.wikipedia.org/wiki/Hyperbolic_discounting
http://www.startupclarity.com/blog/make-time-side-project/