Haircutting and Hair Styling
The four cutting variables
Every haircut is controlled by sectioning, distribution, elevation, and tension. Elevation does most of the work: 0° produces a blunt, one-length line; 45° produces a graduated (stacked) shape; 90° produces uniform layers; 180° produces long, blended layers. A frequent exam trap swaps 90° and 180° - 90° is uniform layering, not long layering. Distribution includes natural fall, perpendicular, shifted, and over-direction; over-direction adds length on the side opposite the pull, which is how a client keeps length while gaining volume.
Guides and texturizing
A guideline is the first strand cut; all others follow it. It is stationary for one-length and graduated cuts and traveling (moving) for uniform layers. Texturizing removes bulk without changing the perimeter: point cutting, notching, slivering, slicing, carving, and razor cutting. Razor cutting softens and tapers ends but is a poor choice on fine, fragile, or heavily lightened hair. Clipper-over-comb blends short hair; the comb stays flat against the head and the blade rides the comb, never the scalp.
Styling
Blow-dry styling is the same geometry in reverse: airflow direction sets the base, and tension plus cool air sets the finished shape. Thermal tools need clean hair, a heat protectant, and a barrel size matched to the desired curl - barrel diameter, not temperature, controls curl size. Thermal burns, on the scalp and on the hands, are among the most common salon injuries with irons and hooded dryers.
Rule of thumb
State the elevation out loud before the first cut. If you cannot describe the finished shape in elevation terms, you are not ready to pick up the shears.