Fortify Until Healed (H) – becomes inactive until fully healed - +25% bonus.Fortify (F) – inactive until receipt of new orders - +25% defense.(Note be careful with this as units may stray into City-State territory and ‘upset’ them Explore (Automated) (E) – unit will explore unchartered tiles until canceled.Embark Mode (B) – move from land to water.Disembark – moves unit from boat to land.Build Citadel (C) –great general builds citadel and is consumed.Build Actions (workers etc): there are many actions such as create road, etc that can be accessed in this menu – usually only applicable to workers, work boats, etc.Attack (Ctrl-A) - attack enemy in target hex.Alert (A) –remains asleep until sight of enemy –+25% defense.Air Sweep – air units attack units in select tile.-33% defense in all terrains except hill, forest or jungle-20% combat penalty for attacking across a river.+25% defense in hills, forest or jungle.There is no limit to the number of units that can be influenced in this way. +25% combat for being close to Great General.+15% combat for every friendly unit next to an enemy-this is supposed to represent flanking and is pretty powerful, so always try to surround an enemy when possible.+15% combat with adjacent friendly units (prerequisite: Discipline policy).Where possible, always place vulnerable units in forest, jungle, or hill tiles.
Clever use of the bonuses will give you a huge advantage. With the limiting of stacks in the game, the use of terrain and other bonuses has become very important both in attack and defense.