AI'm sure there's already a thread here about this but I'm gonna ask anyway! I'm quite new to cake decorating and have only been doing it for a short while! My problem at the moment is I'm making a mario cake topper and now with the warmer weather it's quite difficult to keep the exact shapes you want! Does anybody have any tips!!

Add some Tylose to the fondant.  It will stiffen it up.  It will however leave a bitter taste so not so good to eat.