1/ Suitable equipment for good protection
No doubt your child wants to get kitted out like the goalies they see on the telly, with a short-sleeved shirt, shorts and no protection! But they need to protect themselves.
Explain to them that professional goalkeepers touch the ball just 4 or 5 times during a match, on a pitch in perfect condition, but when they train, they protect themselves by wearing goalie trousers, elbow pads and knee pads so they don't get injured and are able to play on the weekend.