Assuming you want to look radiant, not like you doused yourself in sparkles, avoid highlighters, blushes and powder that contain mica. These can make skin appear overly shiny and reflect too much light in photos.

Blush should be applied very sparingly. You don’t want to look like a ghost, but looking like a clown is even worse. Again, the key here is to blend as much as possible and make your cheek color look as natural as you can. Use highlight on the cheekbones to make them stand out, and hit the bridge of the nose and the brow line, too, to create flattering contours.
White dress with a dramatic top has a tendency to perfectly frame and highlight any uneven skin tone on your neck and decolletage (and even more so in photos)--so make sure to blend your foundation down there, too, and double-check that everything looks seamless. Sometimes, your neck can benefit from a light dusting of bronze, since it tends to get less direct sunlight than your face.