Place your largest baubles first in both colours.
Follow on by placing your large flowers after opening up and bending petals for a reslistic effect.
Place your smaller premium glass baubles across the tree balancing finishes effectively such as gloss, matt and gliter.
Slot in any visible gaps your "pom pom" style pink & red sprays, fanning them out slightly by bending the branches a little for a full effect.
Try to select a smaller red berry style spray for contrast next and add to the tree in the same way. Alternatively use the same "pom pom" style spray but balance colour well.
Add your pre constructed berry tree topper. Bend the branches slightly for a wider spread effect and feed through the branches at the top of the tree so it really nestles into the tree and looks more realistic.