Understanding strategy
Deciding how to set up multiple waves is really where complex tactics start coming in to combat, and some of this depends on personal choice.
A good strategy balances two competing goals:
1. Minimise losses of expensive troops
2. Maximise damage by wise use of expensive troops
For example, sending in 270 cannons or crossbows will certainly maximise damage - but you will lose at least some of those troops which will be costly and time-consuming too replace.
Guides will be based around personal choice of the guide makers of how much they're willing to lose. Or a "value" is assigned to each troop type so that relative losses can be compared.
For example, a guide/simulator might decide that 1 recruit (R) is worth 2 bowmen (B) or 4 militia (M). On this basis, a decision is made that winning the fight losing 200R is as good a result as losing 100B or 50M.
Minimising losses of expensive troops
First, you will suffer at least some losses in almost every battle. This cannot be avoided. Low value units like recruits (R) and bowmen (B) are quick and cheap to replace so you want most or all of your losses to be made up of these low value troops.
Almost every strategy you come across in guides is based around the idea of sacrificing low value units and not putting your high value units at risk except against powerful bosses.
Maximising damage by using expensive troops
On the other hand, your high value units do more damage, and will kill enemies in a smaller number of rounds. This so you want to put as many of them as you can into a battle But you want to use as many high value units as you can without risk of them dying to do maximum damage; this finishes the battle quicker and minimises the number of low value troops you lose. This approach does result in losing more troops in TOTAL, but settlers/bread, bronze swords and bows are quick and cheap to replace compared to steel swords and crossbows.
So you will almost always see large numbers of R and/or B (and C for some special battles) being put in the first wave, all of which will die. You might also be happy sacrificing the medium units, M and LB, and this is often a matter of personal taste.The aim of this sacrifice is to weaken the enemy to a state where you can bring in your high value units without risk of them being killed.
Another popular strategy when attacking with multiple waves is to use only the 200 unit generals for the initial sacrifical waves. The idea behind this is that people will have several 200 unit generals available and so do not have to wait for generals to recover between waves. However, sending in a veteran in the first wave or two can save you some troops even if you then have to wait for it to recover. For the epic fairytale adventures, you've got 12 days to finish them, after all, and you're going to need to queue up some troops in the barracks and perhaps sleep now and again. Again, this is down to personal taste and your gaming schedule.
Finding a Strategy for a Complex Boss Battle
This is a step by step guide for finding a strategy for defeating a boss with lots of accompanying troops. The example battle is the final boss battle on Valiant Little Tailor.
I'm going to assume you've got access to a Major General (MG), a Master of Martial Arts (MMA) and all troop types.
The enemy troops are:
60 Royal Militia (RM) - 160HP, 70-90 Damage, 95% Accuracy, Splash Damage
80 Royal Longbows (RLB) - 60HP, 80-140 Damage, 95% Accuracy, Splash Damage
60 Royal Cavalry (RC) - 40HP, 10-60 Damage, 95% Accuracy, Attacks Weakest, First Strike
1 Evil King (RK) - 30,000HP, 200-300 Damage, 80% Accuracy, Splash Damage
Here's the link to the simulator:
Even 270E are totally decimated by the high damage, splash damage longbows
It's obvious this battle is going to take several rounds and we'll need to clear away the RM and at least some of the RLB before trying to attack the EK.
Those RC are a pain, too, effective killing 40R in the first phase before you can do anything. Maybe some cavalry or a suicide MMA wave would be a good idea.
Look To the End - Killing the EK
Before we work out how to cut down the defending troops, let's look to the final battle with the EK. He has 30,000 HP. A
quick simulation shows that even with 270K you can't quite guarantee killing him in a single round. This is to be expected as the average damage done by 270K is 270*60*1.9=30,780HP.
So, we're looking at 2 rounds of combat to defeat him. In that time he'll probably do 600HP of splash damage, killing 600/40 = 15R. We can save up 2R by using only 13R and adding 1E. 13R+1E have a total HP of 13*40+120=640, so the E might be injured by definitely will not be killed over 2 rounds.
Filling up our MG with 256K on top of those defensive troops and
we do indeed kill the EK in 2 rounds.
So we know if we kill all of the defending troops, we can kill the EK with minimal losses. The question is, do we need to kill EVERYTHING else first, or do we have some room for manoeuvre? The best way to check options is to work out the minimum number of K needed to guarantee a 2 round victory and see how much space that leaves us on our general to attack/defend against the EK's allies.
You can find the minimum number of K needed with a few quick simulations. Or, we can use a little maths to get us in the ballpark area. We want to be doing at least 15K damage each round to kill the EK in 2 rounds. To be on the safe side, let's say we're doing 16K damage. To do this amount of damage we need N cannons where N*60*1.9=16,000 => N=140.
The simulator shows us that 140K does definitely give us victory in 2 rounds. A few more simulations and we find that we need a minimum of 133K to ALMOST guarantee it.
This means we have around 70 troops extra we can use to mop up any remaining troops accompanying the EK.