Ahaha thank you so much, but what turles are you talking about?? You mean the buzzy beetles (the ones with the blue shell) or the koopas (the ones that you encounter in the last episodes)?
In the second case, the koopas mustn't be flipped over! Then, in the first case, to turn over a buzzy beetle you have to counter one of his friends' attack, which can be hard at times. But this is only until you defeat the first one of them, then Luigi will learn a new technique and everything should go smoother.

;).

=O M G!!! WEWTZORS