Dont be afraid to work in your Blackbook homie!!! I will tell you that there is def. more trash in my books than quality pieces! Your blackbook should be a place to experiment with diff. styles, concepts, and color schemes. The great thing about a Blackbook is you dont have to show anybody whats inside if you choose not to. My books are full of half finished pieces and very rough sketches. Often times I just want to get a rough concept out of my head onto paper so that I can revisit it another time. I have found that as I progress, I still revisit things that I abandoned years ago as trash and use them for new pieces often times in ways that are completely diff. from the original ideas I had for them. Maybe you should also consider doing a seperate "Piecebook" if you want somewhere to showcase your skills. Either way....you got to get in that Blackbook regularly and experiment, push boundaries, and PRACTICE, PRACTICE, PRACTICE!!!