A gallery wall works when it has a cohesive thread -- not necessarily a matching style, but some connective logic. That logic might be: a consistent frame color, a single dominant palette shared across all pieces, a subject theme (botanicals, faces, travel), or a chronological or artistic movement grouping.

The most common mistake in gallery walls is starting too small. Pieces that look large on a desk disappear in a gallery arrangement. Aim for a mix of sizes with one or two anchor pieces (18x24 or larger) surrounded by smaller works (8x10 to 11x14). The anchor pieces give the arrangement visual weight and direction.

Lay the arrangement out on the floor before hanging. Photograph it, then translate to the wall. Start hanging from the center anchor piece outward. Leave consistent gaps -- 2 to 3 inches between frames -- for a curated look, or tighter (1 inch) for a salon-style density.