Porosity
Watch how your hair takes water. If water beads up, it takes a while to get fully wet and hours to dry, it's probably low porosity. If it soaks up water fast, dries quickly and frizzes easily, it's probably high. Most people land in between (normal).
Strand thickness
Roll one strand between your fingers. Barely feel it: fine. Feels like sewing thread: medium. Feels coarse or wiry: thick.