You have to start with a crack free ball. Really push and roll the fondant between your palms to get a smooth crack free ball, then lighten up the pressure to shape into a ball.

My trick is to microwave the fondant (mixed w/ tylose) first, then roll it into a ball...not a single crack.

I always have the same problem!!!! It's been bugging me, too! Thank you for asking!

Whenever I'm asked this, I feel bad that I can't give a more helpful answer, but it really is by feel, for me...I sprinkle it straight from the jar into the fondant in my hand and begin to blend it in. If it feels too soft I add a little more, if I've put too much, I add more fondant.

Dark colored fondant will require more than light, and I always add it right before I model something...I don't have it mixed in before-hand.

I think your answer was very helpful! I'll just have to play around with it. Thanks for the advice!