How NOT to disappear! Many people wear subtle things onstage, thinking it's the most complimentary - but when you're a good distance from your audience, they honestly can't see those subtle details and soft colors that blend in. The effect this has is to make your movements seem small, and your character unimportant onstage.
Contrast, brightness, and sparkle are your three best friends onstage. You need to contrast with the stage itself (if it's black, consider more than just a black costume), and your costume needs to have contrast within it to make you and your performance visible to the audience. So a good rule of thumb is that for a small restaurant type audience, or any performance in which you're close to the audience, subtle can be fine. But for the stage, it's contrast, bright colors, and/ or sparkle all the way.