Ranking armies can be built in multiple ways:

1) The first way is the most common way used nowadays, the infantry + healer ranking:

-Rank to brigadier.
- Dismiss all units, buy 25 app healers and the rest of your wage till softcap in low hp infantry ( footmen, spearmen, militia)
- Start training ( using the right scenario), the first runs will be tedious. As soon as you can promote all your units to standard, then first promote your infantry to advanced. When you promote, try always to keep the hp of your infantry around the hp of your healers, by promoting them earlier. At maj gen you'll need to attack rebel villages.
- Anyways, the max rank your healers can have is master, while your infantry needs to get to hero ( usually around Field Marshal or Grand Marshal).

* Note 1: Check the terrains, first of all when buying, try to have at least one terrain
 where both your healers and infantry are good on.
* Note 2: Maj Gen and Lt Gen will be hard, but after that it'll go better.
* Note 3: Ranking is about being active, you'll need to train whenever possible 
and safe to get a high rank. If you can't be active you'll get PvPed a lot and 
then it's not a great idea to rank.
* Note 4: If you don't get kills before Grand Marshal, 
you'll have a few infantry units in excess. The way to calculate earlier how many units 
you'll exactly need at GM goes as follows:
Total GM wage ( wage+hardcap) - 25* 150% (wage of master unit) * healer wage = Wage left for infantry
=> 5560 - ( 25* 1.5 * healer wage) = WLI
WLI/ ( 190% ( wage of hero unit) * infantry wage) = number of infantry units you'll need at GM

2) The second way starts from scratch and uses low wage artillery ( archers, slingers, boomerangmen,...) + healers. Due to the nerfs that have been done to all units, this way has become much harder, and the chance to really loop has been lowered.

An example of this guide is the slinger guide, that can be found on