once you learn how to bracket values in a logical way you will be able to add observation to some reasoning and figure out what values things should be and why.
bracketing means putting a two value jump in value from the lightest plane (direct light) to the darkest plane in shadow (the one getting the least amount of light) If there's a midtone (strafing light or half in light half in shadow) its the value inbetween the lightest and darkest. so if its a white block the plane getting the most amount of light would be no. 1, the midtone would be no.2 and the shadow plane on a white block would be no darker than no. 3.
Day two tomorrow. i'm stoked!