How can fruit be so hard?

My latest mess is some fruit from a demo I watched by artist Bobbi Dubins.
As I am using these paintings as a learning experience I have noted below the paintings what I need to watch out for in the future.

 

not sure why my apple melted all over the cloth, hehe...

 

seems my grapes melted in this one....:)

notes:

need a good drawing for a good painting...block then outline.

know your values

stick to temperature

GOOD PAPER

more water for glazes

Dry thoroughly between layers!!

follow the curves..plan the lay of the land or shape of the object by the swipe of your brush