Empty space is not wasted space. It groups related things and guides the eye.
Room to breathe
Treat this as a starting point rather than a rulebook. Every site, brand and audience is different, so test ideas against your own content and adjust.
Small, consistent improvements beat big redesigns. Change one thing at a time, compare before and after, and keep notes on what actually made a difference.
Before you publish, check the page on a phone, run it past a fresh pair of eyes, and make sure it still reads well with images turned off.