Making effects that read in gameplay, not just in a test scene

An effect that looks incredible on a black background often disappears completely in a real fight. A few things that help:

• Silhouette first. If the shape does not read at 25% opacity, adding more particles will not fix it.
• Contrast against your game, not against black. Test in the actual level, under the actual lighting.
• Short and punchy beats long and pretty. Impact effects that outlast the animation make the game feel laggy.
• Colour-code by meaning. If red always means damage, never use red for a heal.
• Watch overdraw. Twenty large translucent quads stacked on each other will cost you frames on mid-range hardware.

Post your effects here with a clip of them in gameplay rather than in isolation — that is the only test that matters.