I pay close attention to how I do things, especially in recent times how I hold my pens and pencils, and how certain effects can be attributed to the manner in which the fingers are placed. I used to use my index, middle AND ring finger held along the side of writing utensils to write and draw, which produced unsure lines and tired out my hand. I fought my teachers in elementary because I thought I was being smart and that it was more comfortable. I had never held the pencil even NEAR what they hoped to see, with only the index and middle accompanying the thumb. A few weeks ago out of the blue I decided to, and my pictures have been better, my writing has become better, and my inking has improved as well! Even with this, I continue to make adjustments, and yesterday I had a mini breakthrough in terms of keeping my ring finger and pinky flat against the paper while the middle finger slightly holds the pen/pencil and rests a bit on the writing surface. The other two are generally in normal positions, the index fingernail faces upward and touches near the nip of a pen/pencil. I know this sounds confusing, but either way it gives much more support, and helps with creating smoother lines in a consistent manner.
The point of this is, question your work habits. If I had been asking myself the right questions, I feel that my art would have improved years ago, and I would be a totally different artist. Look at the way you hold your drawing utencils, think about your approach to creation, question exactly what you like about the specific work of artists. But that is the true basis for artistic improvement. Ultimately, it's not how much you paid for art media that determines how good you are. You can do nearly the same thing with a 2 dollar Loew Cornell brush as a 60 dollar Windsor & Newton sable brush. It's in your ability to adjust, compensate, and ultimately execute.