Some of most important and best combinations, helpful against a variety of armies.
To think of a successful combination in your civil, just use the best unit of your civil, coupled with a unit that protects it. For example Spanish, has paladin a highly useful unit. We need something to kill harbeldiers against paladins. We can either use archers, hand cannoneers or champions. Take your pick upon what the other may build.
Paladin + HC
However, it is important to control your units. There are instances with amateurs when they make the perfect combination but each of the units get killed by the enemy forces. To make it more clear, let's take an example.
Suppose player 'A' makes Paladins and Heavy Scorpions, obviously a perfect combination. Player 'B' makes Siege Ornagers and harlbeldiers. Now if Scorpions get separated from the Palads and get attacked by Ornagers, there's nothing you can do. So keeping units with each other is the key.
Another tip is to assign a number to a particular unit. I use the number key 1 for my explorer, that is Light Cavalry or Eagle Warrior.
Key 2 is generally for the fast-moving unit among the two and the number key 3 for the other one. For the newbies, it is noteworthy that you can assign any number key to any particular unit or group of units. To do this,
-just select that particular object.
-press and hold Ctrl key.
-press the desird number key.
Now, every time you press that particular key, the unit corresponding to it gets selected.
So, by assigning keys you can exert more efficient control over your units. And once you are a pro, efficiency is all that matters.