Start with the head shape
Draw the hairline
Sketch the main hair volume
Add the part or bangs
Block in large hair sections
Draw clumps instead of single strands
Add flow lines to show direction
Extend hair past the head shape
Vary the length of the sections
Add spikes, curves, or waves
Refine the outer silhouette
Add inner strand lines sparingly
Keep the roots close to the scalp
Leave some gaps for depth
Erase unnecessary construction lines
Shade under layers and near the roots