Practice makes perfect, right?  No.  According to psychology studies, perfect practice makes perfect.  Enhance your skills through deliberate practice.  That is putting your full concentration into what you are practicing.   This as opposed to simply running through the motions or having your thoughts elsewhere while practicing.  Following the pattern of arrested development puts practitioners at the 'acceptable' level of performance, followed by a plateau.  Deliberate practice sets elites apart from amateurs.