How can you make yourself improve at looking? By being regularly monitored by a coach or anyone who is willing to watch you constructively. Also, before mounting a pony, stretch your neck muscles by looking left and right and behind you several times. Then you should extend this self-discipline to make yourself look around between each shot, both during practice and actual matches. Even better, when doing stick and ball exercises and while playing, keep saying aloud 'look around' until you become confident that your subconscious has taken over so that you do automatically between shots.