Next action
Ages ago I saw a great mechanic in a video game, I think for the Nintendo DS but if not it was around that era. Mostly it just had the standard RPG stuff: characters and quests and spells and so on. But the one thing that made it stand out was that it had this amazing "next action" bar. Down the bottom of the screen above all the other important information was just a simple display showing whatever the next thing you had to do was.
Since then I've played games with much more complex quest systems, featuring multiple diverging quest lines, tree views, inline maps and so on. But, as sophisticated as those systems are, none really had the impact of that original one-line display. It was so simple! You could roam around and do other things as much as you wanted, but whenever you felt like moving forward the next action was always there, clear as day.
I think it's easy to get bogged down in complexity, especially when that complexity is actually necessary. Often you need to consider things like which tasks depend on which other ones, time planning, making sure you have the resources you need and so on. But, at the end of the day, the goal of planning is to reduce that complexity as much as you can. While you're in the middle of working, your decisions shouldn't be things like "what is the best thing to do out of all the possible things I could be doing?"
It should just be "am I ready to do the next thing now?"