Welcome to K:CoH.
This is my beginner course for new recruits.
Disclaimer: I am not connected with playkot, I'm also a player who wants to give a few tips base on my personal experience. You are all welcome to post your own tips if you want, and correct me if you have a better advice.
Here goes: (in no particular order)
1. Special Unit MAnagement
The 2nd day special unit "Stormcaller".
---A very useful unit, who can deal +50% damage to infantry units (90 damage)
---be very careful when using it in "Assault". It cost 5 crystal to revive it and you have more or less 1 week to revive him. If he will die, it would be better to just leave the fight than see him die because it will cost you crystals to revive him.
---Very useful in "Tourney". No fear of dying.
---In my opinion, just keep him for castle defense and tourney. They are too precious to lose in assault. Basic and Advance units are more than enough for assault raids.
2. Revival Management
---Advance units (Guardsman, Swordmaster and Shooter) might have better stats than basic units (Militiaman, Hireling and Ranger) but the basic units have faster revival time. It would be better if you bring a few basic units in your assault team to serve as sacrifice and soak up the enemy attacks thereby saving some time on your revival time.
---My strategy is to bring 1 basic unit for every 3 advance units. Even if the enemy kills 2-3 basic unit, it would be faster (and cheaper) to revive them than reviving 1 advance unit.
3. Assault Formation
---I prefer starting in a place with generally light defense.
---It is easier to handle enemies if they come at me one at a time, so in some cases I use the enemy structure to create bottlenecks and just lure the enemy in there. My knights will serve as tanks while my shooters strike at the back and my spearmen deliver the finishing blows.
---Get them as soon as you can... they start of weaker than advance units but they have plenty of upgrades to later make them powerful.
---The best part is that they are immortal, so bring them in every fight and you can even sacrifice them because you do not need to revive them later.
---Unfortunately, they do not participate in tourney and castle defense.
That's it for now... I will add more when I think of more.