Postflight Procedures
After landing
Postflight begins on rollout. Complete the after-landing checklist (flaps up, carb heat cold, trim reset, transponder standby), then taxi at a safe speed with the sterile cockpit discipline maintained until the aircraft is parked. Shut down in the POH order - typically avionics and electrical items off before the mixture, and the magnetos off last, with a brief check that the engine actually stops when the mixture is pulled.
Securing the aircraft
Park considering wind, prop blast from other aircraft, and surface slope. Set the parking brake or chocks, control lock in, gust locks and tie-downs installed per the FBO or POH, fuel selector as directed, and windows/canopy secured. If you refueled, re-check quantity and sump the tanks if the aircraft has been sitting.
Records and discrepancies
Postflight is where airworthiness actually gets maintained. Any discrepancy - a rough mag on shutdown, a brake that felt soft, a new oil leak, an inoperative light - must be documented and reported to the operator or mechanic; do not simply sign the aircraft back in as airworthy. Maintenance recordkeeping under 14 CFR 91.405 and 91.417 requires that discrepancies be recorded and that inspections and repairs be logged. If you flew a VFR flight plan, close it: with ATC in flight, or with Flight Service on the ground. An unclosed VFR flight plan triggers search-and-rescue action.
Debrief yourself
Note fuel used versus planned, block time, and any airspace or ATC surprises. File a PIREP if you encountered significant weather or turbulence - it costs one radio call and may save someone else a bad approach.
Trap
The frequently missed item is the VFR flight plan closure and the discrepancy write-up. Both are regulatory, not optional courtesy, and both appear as "what should the pilot have done" answers.