tinyliny, I use prismacolor pencils which are pretty dense and don't break when applied with hard pressure. I just add A LOT of layers, then go over most of the drawing as hard as I can with a lighter pencil to blend everything. Then I go back over the darker areas with a darker pencil. Kinda hard to describe, but it's just a matter of playing around with different layering effects. One thing I have to be careful of is the paper curling up because of all the layers. Thick bristol paper works great, but this colored pastel paper I am using does curl up a little.