Basically XP points are given for playing the game (#of holes, # of shots) so the best and cheapest way is to just play the game.
You can increase the XP you will receive by;
- if you're playing on mobile, watch the 15-30 sec video after a round/game. It will add a random amount of extra XP points and is basically free.
- purchasing XP boosts in the ProShop. They look like bottles of energy drink and will increase XPs by 5-50% for a certain length of time depending on how much $$ you spend.
- purchasing a Plus or Premier Membership in ProShop that will increase your XP for 1 month to 1 year, again depending how much $$ you spend