I like your eggs. I mean the lines, mine lines are made with hair but yours very accuracy and clean.

You are using the wrong tool, pen-like brush preset only for linear drawings, and a more air-brush like brush for shading. Don't use opaque lines to portrait shadows, use a brush that blends and/or has transparency. If you want to know how good a brush is for achieving good rendering, look how easy you can do a 5 values chart (five squares of different tones of gray, where the darkness gradually increases every square) with said brush preset.