Most brides come in with a picture of a veil and leave with a different one. That is fine. A veil is decided by the dress, the room and how much you want to move.
Start with length. Elbow length stays out of the way, floor length frames the dress, and a cathedral veil is for a long aisle and a photographer who knows what to do with it.
Then the edge: raw cut tulle disappears, a rolled edge draws a fine line, lace gives the face a frame. Last comes weight. Silk tulle falls, nylon tulle floats. Try both in daylight.