Hoping someone has some ideas for me..... every time i cover a square cake in fondant my corners always crack? Is there a secret to it or will i get better with practice? 

Do you mean they crack like they rip apart and you can see the cake under them, or do they just look like the fondant is rougher in those spots?

Yeah, what she ^^ said.  If you could post a pic of what you are having trouble with maybe we can help.

Sorry dont have any pics. But yes like rip apart & can see the cake underneath.......

sounds to me like you are rolling the fondant too thin.  Have you tried keeping it thicker?