Anyone have any tips on how to do this smoothly? I want to make a moon but not sure if I should just cut it in half and do half of a moon face on the top of the cake or try to attempt the whole ball covered in fondant... the whole ball would look a lot cooler (if done right that is...) Any help or suggestions?

I've done it twice and it was smooth. Elevate the ball on something small before covering the fondant.