Completing any song on any difficulty setting gets you a crown:
Effect - Code
Taiko March - Get 5 Crowns
Don Rangers - Get 10 Crowns
Ridge Racer - Get 15 Crowns
The Genji and The Heike Clans - Get 20 Crowns
'Oni' Difficulty - Get 25 crowns
Use standard controller
Instead of using the drum controller, a standard controller can be used as follows. Press the D-pad for red hits, the D-pad + X, Circle, Square, or Triangle for hard red hits, and L1, L2, R1, or R2 for blue hits.