This is one of the rarest achievements in the game, as it is entirely luck based.
You will earn EA coins when you play with your created golfer, and these can be exchanged for boost pins in the Pro Shop. Only buy the cheapest packs as these give the most bronze pins, and all packs only give the same amount of pins so this represents the most economical way of getting boost pins.
You will be trying to a fill an entire set of pins to complete a bronze set, so i would advise selling any that are not bronze pins when you go through the packs.
You only get one chance to sell pins when you first open a pack, so choose wisely.
You can purchase EA coins through your XBL account if you want to try and speed the process up - but it's still random what pins you'll actually receive, so this may only be an option for people with deep pockets!