AMy fondant is always dry and cracking..what am I doing wrong?? I use corn starch because it gets too sticky..any tips?

Is it homemade? You may need to add in some glycerin.

If it's store bought, are you kneading in a tiny bit of vegetable shortening (crisco) ?

Corn starch is a drying agent.  I won't use it with fondant at all.  I roll on a smear of crisco, only.

ANo its bought. Don't use vegetable shortening. .so that will make it better? It doesnt get sticky at all? How much do you put in?

I just rub a small amount on my hands as I knead the fondant, repeating until the fondant feels smooth. 

I never find that it takes very much if the fondant is OK to begin with.  If you add a lot, you ruin the consistency of the fondant and it will be worse than ever.

ASome way to use cornstarch, Don't! It will dry it out. Use confectioners sugar and keep a liitle Shortening on your hands. Regards:-)

all good answers--i'm one who recommend cornstarch kneaded into fondant for making things like flowers & bows etc.but not for covering a cake--

sometimes all you need to do is let the blob of fondant air dry a tad -- like for black or colored or sticky fondant that often works for me --