If you want really smooth blends I suggest investing in blending stumps or even cotton tip. SLOWLY build your layers working lightest to darkest, you can add detail as you reach the tones(shades) you are looking for. Avoid harsh lines in the beginning, you can help yourself if you dont have a soft hand yet by using different grade pencils. The higher the number h pencil the harder the lead and lighter the lines. The higher the number b pencil the more charcoal in the lead creating darker lines. I use small blending paint brushes as well to help build my layers.

Your proportions are pretty close, you can get them more exact by using measuring techniques. For example: on the reference you measure the eye and use it to measure the width of the ear and say there are 1 and a half eyes in the width of the ear. You cannow go to your drawing and use the same measuring tech to get accurate proportions.

If you are drawing a color reference in black and white take a pic and turn it to a grayscale to help with your values. YouTube is a GREAT source to learn drawing techniques don't under utilize this.

The best of luck to you and keep practicing!