A page can feel crowded long before it runs out of space. Several equally strong elements compete for the same glance, leaving a reader unsure where to begin. A useful design exercise is to remove one element before adding another.
Start with a small page containing a heading, an image and a short paragraph. Decide which item deserves the first look. Give that item enough surrounding space to make the choice visible, then arrange the remaining material in a quieter rhythm.
Compare two versions at the size a reader will actually see. A layout that looks balanced when enlarged may feel fussy on a small screen. Read the words as well as inspecting the shapes; the page needs to work as a piece of communication.
Keep a note of what changed and why. The purpose is not to find a universal amount of empty space, but to make a deliberate decision for this particular page. Restraint becomes useful when it gives the content a clearer voice.