To do this you must gather a lot of wood first. You can either use any cheat for this or you 
can use your villagers to do this.

When there is one unit left for you to reach the Population limit select some of your villagers
and build the structures which are used to terrain the units you want.(You must have one building
for each unit you build after population limit. Eg: you need 11 archery ranges to terrain 10 
archers after the limit).

After building enough buildings hold down the CTRL key and select the building you have built.
Now you can quickly change your selection by  pressing TAB.

Now you can start terraining units you want by selecting the appropriate icon(using hotkeys 
is recommended). When you have selected one icon in one building once Quickly change your 
selection(using TAB) and select a unit in that building and continue this action until you
have selected one unit in each building.

If you succeeded in selecting one unit in each building Before the first unit is created you 
can build as much units As you want.(It will become easy if the first unit you created Is a 
unit which take a lot of time to terrain. Eg: PRIEST,ELEPHANT etc.). 
Practice will make you better in doing this.