Once you get Festlig Purple and the grey suit to wrap it up in, it's just a matter of deciding which kind of shirt you want to go for. White is never wrong, and always handsome. But if you can carry the weight you could go for a patterned shirt, eg. very small checks, thin lines. Or loosen things up with a lighter tint of purple. But don't colour invert tie and shirt – making the shirt darker than your tie is a better choice for your night out. Be bold, you'll be fine