I don't think you need to use the one at a time approach if it doesn't work for you.
Quilting, especially quilt design, is an iterative process. Sometimes it requires taking a break and working on something else for awhile....at least that's what I tell myself while buried under all these UF Os.
But I imagine that the best way to approach finishing is to set a timeframe for when something needs to be done. Then reward yourself when you meet the goal.