Those hints and notes have been collected from several sources, from game manual to personal tests within the Editor.

Since this game is quite complex and not fully explained in the manual, I found useful to collect all the notes classified as "tricky" in order not to forget them.

Many more could come with more games and editor researches. Feel free to add more info or correction if I happened to be wrong.

Rifles Shooting

• Peasants or melee units in the Building with rifles defences: 0 damage bonus
  
• Shooters, no matter the type: damage bonus regarding the building's initial shooting damage
  - 1 shooter inside an initial 20 dmg building → +6
  - 1 shooter inside an initial 30 dmg building → +3
  
• Maximum Bonus dmg = 145. Can't go beyond
  
• Same damage reduction as on the field, depending on the distance (see game manual)
  
• Defensive properties available inside a building. Harquebusiers are the best inside because of bullet protection.
  
• Rate of fire in a building depends on the number inside, not the type.
  
• Buildings grant armour bonus, approximatively dmg/2. Units are thus more protected inside a building.
  
• For Buildings with rifles defences, shoots come from the windows. Therefore, there are dead angles where the building can't shoot.
  
• Buildings shoot only if there is no creation or upgrades inside.
  
• Only Log Cabins and Towers can stop attacking. The other buildings attack automatically
  
• If Cannons in the building (Log Cabin II, Forts and Fortresses), the won't shoot if enemy is too close → Range restriction
  
• Tepees can only shoot to one direction: entrance's direction

Bows Shooting

• No damage bonus for Building with bow defences
  
• Rate of fire in a building depends on the number inside, not the type.
  
• Buildings grant armour bonus, approximatively dmg/2. Units are thus more protected inside a building.
  
• Defensive properties available inside a building. Pikemen are the best inside because of bullet protection.
  
• Range for Towers: between less than a screen (normal view) and at the bottom. If enemy too close, won't shoot.
  
• Bad precision if the target is moving
  
• If Rifle Shooters capture a bow building, the will shoot bullets and bonus damages probably apply as for Rifle buildings (Max 145)

Capture

• All foot units can capture buildings, no matter the type. Cavalry units can only capture Forts and Fortresses
  
• No matter the Units' HP inside, works on a % basis and on Unit's Storm Force (available in Unit description with “U” hotkey) :
  - If 1 enemy inside → 1 unit is enough to kill it, 1 more to capture building (if same Storm Force)
  - If full building population inside → 10 units to kill 1 (if Same Storm Force)
  - 100% pop=10:1 ; 50% pop=5:1
  - If 30 Storm Force attackers vs 10 Storm force defenders, 1 attacker equals 3 10-storm-force
  attackers, which means you'll need 3 times less attackers.
  - Opposite works the same way: if a 30 storm force defender, you'll need 3 times more men
  with 10 storm force (30 for 1 if 100% pop inside).
  
• Best units to protect and storm buildings are Native American Chiefs with 100 Storm force. No matter the number of enemies, 1 Chief = 1 slot off.
  
• Pikemen are the most suitable solution, with good balance between storm force and price.
  
• Units with bullet bonus protection are the best for capturing buildings since they can survive more than the others while approaching the building.
  
• If a production building is captured, can only produce if of the same culture.
  
• The number of enemy units present inside the building is only revealed if our own units are trying to capture.

Attack

• Shooters can shoot through the building's walls and windows:
  - Rifles inflict half damage than usual to units inside, precision and power depending on range, as on the field
  - Arrows are set on fire to burn first. 15 fire arrows burn a building.
  - If building already in fire, arrows inflict very low regular damages to the building or to the units inside?
  
• If mouse pointer doesn't change into a Sword, that means units are no longer present inside.
  
• Cannons and Fire Arrows can set a building on fire. Therefore, a Fortress' upgrades such as Stables or Arsenal can be destroyed since they are extensions of this building. The upgrades will no longer be available and will have to be researched again. This can be avoided if the building's damages don't exceed a certain amount, and quick fixed by peasants.

Fight Tests

1. Fusiliers (196) VS Aztec Tower (30 pikemen with bullet protection)

• Max range:
  - all fusiliers dead
  - 0 tower casualties (only -1 hp per bullet damage)
  
  
• Close range:
  - 30 fusiliers dead while marching to close range, all dead after
  - 19 tower casualties

2. Harquebusiers (196) VS Aztec Tower (30 pikemen with bullet protection)

• Max range:
  - all harquebusiers dead
  - 5 tower casualties (only -1 hp per bullet damage)
  
  
• Close range:
  - 0 harquebusiers dead while marching to close range, only 9 after
  - first salvo killed 10 Aztecs
  - Full tower casualties in only 2 salvos

Conclusion: even if Fusiliers are more powerful, they cannot survive long enough to be able to reload and keep on shooting to decimate an entire tower population. For both tests, the max range is to the tower's advantage since the rifles damages and the precision are too low.
The best unit for capturing a building is the Harquebusiers. Thanks to their armour, they can survive long enough to come at close range, inflict maximum damages and either reload for another salvo or enter the building. Regarding the tests results, it is better to wait for another salvo and only lose 9 men, resulting in an enemy empty building, instead of losing more men by fighting for the building's capture (would have been approximatively 120, according to the % calculation).

• Close combat units won't move at all
  
• Ranged units will shoot without moving
  
• Enemy can't capture a mine or peasant if troops around → usefulness of guard mode
  
• Troops won't protect a building's entrance if not packed in front of the door. The guard mode must manually set to protect the entrance. However, a few enemy troops may enter
  
• Guard mode can be used as a “Follow mode” since this latter is unavailable. This can be useful to provide a troop supply to a battalion in formation. However, to be able to “fix the formation”, the guard mode as to be disabled first.

• A unit will search and fight an enemy if he enters in his zone unless the unit is set in Stand Position or Guard Mode
  
• If the enemy is in the unit's last zone (check manual), the search and fight will happen only if facing the enemy. The last zone is thus an oval.

• Frigates are strong against buildings but weak against Caracks. If peasants are fixing the building, since the Frigate's rate of fire is too low, the building will survive.
  
• Caravels can't destroy a Log Cabin II if peasants are continuously fixing it. In this situation, if the Caravel is in range to the Log Cabin II's canons, the Caravel loses.
  
• Caracks are the best ships, on sea and for destroying builds at “short range”. They can destroy easily a Log Cabin or a Harbour with their high rate of fire, since the peasants won't have enough time to fix it.

• Teepees can be recycled, even when getting captured or burning.
  
• Haida's totems allow troops in full rout to gather around it.
  
• The closer the faction last building, the bigger the morale. That is why it is easier to defend a base than attacking an enemy's one, since our buildings are far. In that way, Totems are useful
  
• Trade Posts generate some gold over time, which can be the only source of gold for native civ that can't build mines.
  
• Almost every buildings give a bit of population room. It can be a workaround if extra Dwellings aren't affordable.