Get some brightly coloured spray-paint. Neon pink, gold or whatever. Paint the whole bike with it, obviously try not to get it in the mechanically sensitive par

Get some brightly coloured spray-paint. Neon pink, gold or whatever. Paint the whole bike with it, obviously try not to get it in the mechanically sensitive parts but otherwise coat the whole thing. No-one is going to steal that, it will still ride just as well.