Find a way to get even shading

Tried with a 2B and a 4B. A bit smoother if you shade across the area and then rub out the shading that went over the edges. It’s not that different, though. If you need to keep within the edges then it’s best to shade both ways (rectilinear directions). This covers the uneven marks a bit. The biggest problem is keeping the pencil at an equal angle and at equal pressure.

Shading swatches