I am always a little amused by the proclamation "I can't even draw a straight line" often made by someone discussing their lack of drawing ability. Why would a straight line be any indication of drawing skill? Hardly anyone can draw a perfectly straight line, without a ruler, nor do they need or want to. Straight lines are boring.
What I strive for are confident, strong, interesting lines. That is why I like drawing with a pen or fine tip marker. Pencil lines tend to be a little weak, in my opinion. I know, I know—pencil lines can be erased. Pen lines can't, but they can be wadded up and tossed away. Yes, you are allowed to do that.
Here are three kinds of drawn lines:
The first is the kind of pencil line that most beginning drawers make—a sketchy line, which is actually a series of little short lines. Drawing teachers will tell you to quickly move beyond that kind of line. Next is a continuous pencil line. Stronger and more definitive. The third is a line made by a fine tip marker. It is basically the same as the second pencil line, but being ink it just seems so much bolder and stronger.
I challenge you to draw with ink. It's not that scary and, as I said, there is no reason not to toss your drawing if it is just awful. For me the quality of the line is what I am most interested in. Is the proportion or the perspective off? Probably. I don't care that much about that. A beautiful line—that's what I want. Look at this Picasso drawing.
Was he concerned that the hands are way too big or the leg too short? No, not so much. But look at that line. Beautiful!