Scribbles and Doodles

I don't know how I can still make time to draw- no doodle stuff like this and actually sacrificing sleep. I actually googled logos of some of the bands I like and am decided to draw them on my canvas sling! Cool idea eh? Problem is, how can I not screw up? So I tried drawing once, in my diary. Not going to draw it on my canvas sling anytime soon though, it will be way too time consuming since I will make hell sure that it doesn't screw up.