Flight by Reference to Instruments
Two ways to describe the same thing
Instrument flying is taught either as control-and-performance (what the airplane is doing: pitch, bank, power, trim) or primary-and-supporting (which instrument gives the primary pitch, bank, and power information in each attitude). Be fluent in both, because questions swap between them. In straight-and-level flight the altimeter is primary for pitch; in a constant-airspeed climb the airspeed indicator becomes primary for pitch and the altimeter supports. The attitude indicator gives attitude directly, while the VSI and altimeter show trends and performance.
Maneuvers and scan
Know the four fundamentals, standard-rate turns (3 degrees per second; two minutes for 360 degrees), timed turns using the turn coordinator plus clock, and partial-panel technique. Recognize magnetic compass errors: ANDS (accelerate north, decelerate south) and UNOS (undershoot north, overshoot south when rolling out on a northerly heading). Spatial disorientation illusions - somatogravic, somatogyral, coriolis, autokinesis, vection - explain why you must fly instruments, not sensations.
Worked example
A standard-rate turn: 3 degrees per second. At 120 knots TAS, turn radius is roughly TAS/200, about 0.6 NM. Lead your rollout accordingly rather than waiting for the heading to appear.
Trap: identifying the turn coordinator as a source of bank angle - it shows rate of turn and yaw, not bank. Another is assuming the attitude indicator is vacuum-driven in every airplane.