A child should be able to draw it from memory. The best flags — Japan, Canada, Switzerland — work because of what they leave out.

Most great flags use two or three colours. More than four and the flag starts to look like a patchwork quilt at a distance.

Text is unreadable at distance. State seals look muddy when printed on fabric. Use a bold symbol instead — it travels further.

Every colour and symbol should mean something. Red for courage, blue for sea or sky, white for peace or purity — the narrative matters.

Your flag should be unmistakable among nations. Avoid generic tricolours unless the colours or emblem make it unique.

If it looks like another flag flipped or recoloured, start again. Distinct identity comes from a distinct visual idea, not incremental variation.