Hi ChocoZell,
Sounds like you are trying to stretch yourself artistically. Which means...drop your crutch! Let go of what you know, and practice what you see. You say you aren't good at manipulating "basic blobs of color" yet. Fair enough. I recommend a few excercises to help you see in a different way (straying from you linework method).
Have you tried setting up a still life, or asking a friend to model for you? Heck even a self portrait will will work for this. Set up one light source for your subject. Dramatic is best...so maybe a darkened room with that single light source.
Let's start with BW for now. Try working with ink or charcoal...keep it simple. When you are looking at your subject focus on seeing the dark areas vs the light. Ink/draw what you see (NOT what you know). The dark will help form the light. For this exercise, you don't necessarily need to worry about the grey areas. This is an excersice in seeing how shadow and light work together to create forms. You can help break yourself of linework...or rather you are just adding another skill set to your bag of tricks.
I hope this was helpful to you in some way.
Happy Painting!
:)