Major Projects
Quick Wins
Fill Ins
Time Sinks
An impact matrix creates a structure around prioritizing tasks. You analyze the tasks that you have on your todo list based on time and impact. I personally break tasks down to max 4-6 hours each. I've found it helps me get into and stay into flow state really well. I use it a few times a week for both work and side project stuff.
Quick Wins are the tasks you want to do first. You'll find this term used a lot in startups and it's because these are the tasks that'll get you the furthest the fastest.
Major Projects are still valuable but take longer. I've found that reframing these tasks can move them into the Quick Wins quadrant. eg. Can buy solutions or break them down further. You can also re-think of the task and how to get 90% of the way with only 10% of the effort (from Michael Seibel's podcast).
Fill Ins are tasks that you do when you have no other work to do and you're bored.
Time Sinks are tasks that you don't do. They're time sinks, a waste of time. Delegate if you're on a team or put them on the backlog.
If you're working on solo projects, then you don't have the option of delegating anything, so I would recommend you use the quadrants to prioritize work but do all the tasks in the order: Quick Wins, Major Projects, Fill Ins, and Time Sinks.