Operational procedures: from site survey to shutdown
Pre-flight
Good operations start away from the airfield. Do a site survey - on foot or with good imagery - to identify hazards, obstructions, the take-off and landing area, and where bystanders will be. Check airspace, NOTAMs and the weather (wind and gusts, visibility, precipitation, temperature), then the aircraft: firmware, props, structure, battery state, storage, gimbal. Configure the failsafe and return-to-home altitude deliberately, and brief the crew on roles, communications and the emergency plan. Have a risk assessment and a checklist, and use them.
In flight
Maintain continuous VLOS, keep clear of uninvolved people, respect the 120 m ceiling and your own limits, and monitor battery, signal and telemetry trends rather than single readings. Fly predictably; do not chase the perfect shot. Expect failures: link loss (auto-RTH or land), loss of GNSS (attitude mode, drifting), a fly-away, a battery emergency, a fire. Each needs a rehearsed answer.
Post-flight
Log the flight, inspect the aircraft, cool and store batteries correctly, and report anything that went wrong - serious incidents go to the AAIB and occurrences to the CAA.
Trap: setting RTH altitude 'high to be safe' so that it breaches 120 m, or so low that the aircraft returns into a tree. And believing RTH returns to where you are standing rather than to the recorded home point.
Rule of thumb: set RTH altitude above the tallest obstacle within the return path plus a margin, but below 120 m - and test the failsafe deliberately at altitude before you ever need it.