Hierarchy is subtraction
Most weak layouts are not missing emphasis. They have too much of it.
Emphasis is a budget
If three things shout, nothing is loud. Hierarchy is not the act of making the important thing bigger; it is the act of making everything else quieter. Most weak layouts already contain a strong idea, buried under three competing ones.
Two steps, not one
Choose one primary element and demote everything else by at least two steps of size, weight or colour. A single step reads as an accident. Two steps reads as intent.
Hold the line
Resist adding a third level until the first two hold on their own. When a page needs a third, ask whether the content itself has too many jobs.
Contrast is a budget. You get to spend it once.
Take a layout you are working on and delete every emphasis: one size, one weight, one colour. Add emphasis back one decision at a time and stop the moment the page reads.