You cannot always kill procrastination. I recommend drawing when you have free time or when you're bored. You could also find inspiration which really encourages me to draw. I feel inspired and fired up to draw when I see art I love. Paste and print some of your inspirations into your sketchbook. This will keep the inspiration everywhere you go, and hopefully dull the procrastination habits.
I think you should try making your lines less stiff and more sketchy. Wonderful drawings but your technique seems a bit rusty- though everyone has their own style.
