The key thing that will help you with this painting is to think about painting shapes instead of trying to paint a peony. Breaking the subject down into shapes helps to activate the creative side of the brain. 

It's much easier for your brain to focus on painting shapes than to overwhelm it with painting a whole complicated peony. 

The other important thing is to be sure to get the correct colors and values (light and darkness of a color) in the right spots. Nailing the correct values will give your painting a more realistic look. 

As always, if you have questions, I'll be happy to help! 

Happy Mother's Day!