/ic/ - Artwork/Critique

My attempt at this straight lines always ends up with me creating lines that are slightly angle and then curve near the end. The more I try to find the balance between speed and accuracy, the more I seem to just mess up and forget to use the shoulder as the main mechanism behind the motion.

I'm gonna go back to grinding after this post, but I could use some advice and points if anyone can offer them. I'm just not sure what it is that's causing these frayed lines at this point and how I can improve on it.