Those lines are pretty nice already. I found that when I relax more and start moving my pencil before putting it on the paper it start tapering. Also, I think of my pencil as feeling like a brush and that works pretty well too. So relax and don't push the pencil down, let it fall naturally on the paper, as if it just happens to be there while you're moving.

There will come a day where you cannot rotate the "paper" because it might be a wall or a canvas or other object not given to easy rotation. But no need to go nuts. Rotate the page now, and once your quality and speed is up to snuff, the technique is right, then practice the odd angles but still don't go crazy. You'll be able to rotate the paper for a while yet, and iPads, and drawing tablets all do touch now so there's still a good reason to rotate the page. I say wait to practice it because killing bad habits is way harder than learning good ones right away. A bonus of rotating the paper is that it kinda divorces you from the subject so you get used to seeing it from different points of view, which can help reveal imbalances and flat or stiff work.