BASICS before any PvP (BoG/BoC/SvS/KE): switch a development defender (e.g. Shajar) to a COMBAT defender; turn OFF subordinate-city linkages ('automatic fight') if you intend to ghost all troops; review march presets (e.g. when using a march-size-increase item); turn off rally notifications (Settings>Options>Alliance War Setting) so ghosting doesn't flood chat; use 1-hour buff items (Attack/Defense/HP/March-size) and set a timer since they expire in 1h; switch Monarch Gear presets per troop type; switch Monarch Talent combat-vs-development presets (esp. the Lv22 Subordinate City Attack talent); switch Civilization Treasure (Globus Cruciger=healing speed, or Tutankhamun's Dagger=march speed to monsters for BoG); switch Blazon (mounted PvP set-buff); activate Shrine 'King's Protection' offer buffs; swap castle decorations that carry buffs; use Alliance Science skills (e.g. 'Mighty Force' = +attack); use the Dragon active skill (high-level, 3rd talent); change Culture to Japan (offense) or Russia (defense) for the subcity buff; switch Mayors if leveling via mayor. SvS/KE ONLY: spend resources first (essential before ghosting the whole army, and safe even otherwise in case you lose the defense); REMOVE the defender if you ghost the whole army, otherwise the defense general dies during the defense.
Original research source: Evony Guide Wiki