/ic/ - Artwork/Critique

Posted a little bit ago about how I went back to drawing on paper from a tablet since I'm just beginning.

This is my drawing and reference. One thing I noticed that I am having a little trouble with is getting proportions right. Most of the process of drawing this was trying to measure out everything to an accurate proportion. While this overall was an improvement from what I was doing on tablet, I'm unsatisfied with the proportions. An example would be that I drew the forehead a bit too small.

Is this something that just needs some grinding that I'll get the hang of eventually? Or is there something specific I should be doing/reading.