Update - Trillium Almost Done!

I have been working more on the trillium and am getting closer! 

This is what it looked like yesterday (above), as I continued to add layers of color on all three leaves.

And this is what it looks like today, after additional layering, mostly the olive green. I added dark indigo (9201-157) to the mix to deepen the shadow areas and still need to blend those in more as well as darken more, especially on the leaf on the far right. 

As I have read in many instruction books, using a dark blue/indigo or sepia is a better way to deepen shadow areas as it provides depth and doesn't make it as flat or stark as black.

I need to set it aside and look at it with fresh eyes later or tomorrow, pull out some highlights and further darken shadow areas, then make sure the blending works overall.

This is the part that I find most difficult and most rewarding. If it continues to come together and I can 'see the end' then it gets exciting. However, often at this stage, I find that I blend too much and it gets overworked.

What do you find to be the most difficult part of a painting or drawing?