Unlockables:
Royal & Links Country Club - Get up to the Grand Rank
Dino Park Golf Course - Get to the Silver Rank
Manual Replay Mode - Get to Senior level in challenge mode
Autumn Pagoda Coarse - Get to Beginner level in challenge mode
Olive Coast Coarse - Get to Mid-Rank level in challenge mode
Golden Desert Coarse - Get to Senior level in challenge mode
Unlock 5th loyalty heart for a character - Get a Super Win against them vs a regular win(get a -3 before the match is over)
Open new ranks for challenge mode(mid-rank, senior, ect.) - Win matches/tornaments with a star. Once you gain enough stars you will unlock the next level
Unlock Easy Mode for Challenge Mode Lose multiple matches/tornaments in a row in challenge mode. There is no negative to this and can be changed under the options menu.

Unlockable Characters:
Defeat any of these characters in a VS match in Challenge Mode to Unlock them

Alia - Defeat in VS mode (Beginner)
Shu - Defeat in VS mode (Novice)
Julie - Defeat in VS mode (Mid-rank)
CJ - Defeat in VS mode (Senior)
Patricia - Defeat in VS mode (Grand)
Logan - Defeat in VS mode (Bronze)
Holly - Defeat in VS mode (Silver)
Roger - Defeat in VS mode (Gold)

Easy Loyalty:
Select Challenge mode and pick match play (doesn't work with tournaments). When it is your turn press select and start to give up. Keep doing this for 3 matches and lose. You will get loyalty points even when you lose the match. Keep doing this to max out all the chatacter's loyalty.

Free power shots:
This trick allows you to get a free power shot: when doing a power shot, set the power and impact as you normally would, but the moment the club hits the ball (after setting the shot impact), press triangle. If this is timed perfectly, the power shot you are using won't decrease the number of power shots remaining. This does not affect the shot at all, and it doesn't have any negative consequences if done incorrectly. This must be used during a power shot or it won't work.