Attacking / defending bonuses.
Hero level gives 0.5% bonus per level. Meaning that if you attack with a lvl 212 hero, you will get 106% bonus. To get the bonus while being attacked, assign your high level hero to “training”.
There are runes that give you 20% bonus for attack and hp.
Then the researches from academy, Honed Blades and Vigor. Each level of these researches gives you 5% bonus for attack/troops hp.
Troop tiers
Obviously, tier 1 dies to tier 2 that dies to tier 3. Tier 2 are horrible for ratios. Best situation is to have tier 1 and tier 3. Build tier 2 if you are a hugger, you only care about your might value.
Some mechanics regarding walls. When you attack a player that has both troops (open) and walls. The wall will get attacked first. Send only one type of troops, for example mounted units. Send a mix of units if you are fighting against soldiers, not wall.
For defensive, when you get attacked by a mix of troops, it is best to send one of your tier 1 troops to your second city. This will help with the ratio.
Defenders will generally see a 30% advantage if everything else is equal.