Let the content set the layout
Begin with a narrow viewport and add columns only when the content has room. A breakpoint should resolve a real crowding problem, not match a particular device model.
Use flexible widths and minmax grids so cards can adapt without a long list of special cases.
Protect reading comfort
Keep paragraphs at a comfortable measure and allow headings to wrap naturally. Scale typography with restraint so it stays readable across widths.
Give touch controls enough space and avoid placing important actions too close together.
Test changes where they break
Check the page at narrow phones, landscape widths, tablets, and large monitors. Look for horizontal overflow, clipped content, and awkward empty gaps.
Use browser dev tools and at least one real device when available; responsive behavior depends on more than screen dimensions.