How do I choose a backsplash tile that works with the countertop?

Pick the countertop first, then the tile, never the reverse. A busy stone wants a quiet backsplash; a plain quartz can carry a tile with pattern or texture. Hold the actual tile against the actual slab in the kitchen light rather than comparing two samples in a showroom, because showroom lighting flatters everything. The most common regret is matching them too closely: a backsplash the same tone as the countertop makes the whole wall read as one flat surface.