This is where I am stuck

Alright guys this is a WIP and I have been using that PK coloring method but I really dont understand what to do next. I understand compliments and I understand what to shade with but I just have no idea how to go from this to the finished product.

Some help would be greatly appreciated. I just dont understand the random marks (from what I can see) can come out looking so well thought out... >.<

ALSO this is a WIP for Caroline and sorry guys about not posting anything in a while but I am at a sort of artist block. I mean this took me 2 days to get to XD

Hope to get some answers/help from this :3