How should I open my pool for the season?

Clean, fill, and shock in that order. Skim off winter cover crud, pump standing water, remove and store the cover, then reinstall plugs, fittings, and ladder. Fill to the right level, then vacuum, brush, and skim. Balance alkalinity first, then pH, then shock (non-chlorine if impatient). Run the filter for 24 hours, test again, and add clarifier for cloudiness or algaecide after shock if algae appears. The only real mistake is skipping balancing before shocking.