Ditch the overpriced, overprocessed prom hairstyles this year. We've rounded up 20 of the trendiest formal hair looks with step-by-step tutorials and advice for pulling them off. If we can offer you only one prom hair tip, let it be this: Less is more. That goes for hairspray, teasing, and impossibly tight curls. The best formal hairstyles should let your face and gown do the talking.