I played CKII for a long time but I have never able to use combat tactic efficiently.
Eh, most players don't. Min/maxers like me obsess over optimal army composition, but generally the larger size army can usually win when both sides use mishmash armies (which is often the case against AI; of course, Mongols are always the exception), assuming other factors are fairly even (not too overwhelming terrain advantage, flank leaders aren't 20~30 Martial god-generals with awesome combat traits vs scrubs/nobody).
I dont even understand how it works. Yes, I read wiki but still couldnt get it. For example, I am Shia and I want to use desert ambush tactic, then how many percentage of camel, infantry, v..v.. should I have in a stack?
What do you mean? The
wiki page spells out exactly what requirements you need:
1. The flank leader needs to Arabic culture. Doesn't matter if he's Shia or Sunni.
2. The battlefield needs to be Desert Terrain.
3. The combat phase is Melee Phase.
4. At least 10% of total army in that flank is Light Cav or Camel Cav.
5. At least 10% of total army in that flank is Light Infantry (so generally you need levies or mercenary to achieve this, not purely retinues).
Each of the three flanks roll different tactics, so if you want Desert Ambush to trigger in all three flanks, all three flank leaders must need the above requirements.
Optionally, if you meet the below requirements, your chance of triggering Desert Ambush (out of your total pool of available tactics during Melee Phase) multiplies by 150%:
1. Flank leader has 10+ Martial AND at least 20% of total army in that flank is Light Infantry AND at least 20% of total army in that flank is Light Cav or Camel Cav.
2. Flank leader has 10+ Martial AND at least 20% of total army in that flank is Light Infantry AND at least 20% of total army in that flank is Light Cav or Camel Cav AND the flank leader has Trickster trait
The two modifiers can be stacked, which will boost your chance to trigger Desert Ambush. If you can somehow avoid other Melee Tactics by purposely NOT meeting their minimum requirements, then you can further maximize your chance of triggering Desert Ambush.
And btw, should I really use camel? Even after a lot of upgrade for the camel cavs, they seems to so...underpowered. The light cav I have is just slightly weaker in skirmish and melee stage while superior in pursue stage compared to my camel cav. I dont even know if I should delete the camel cav troops and give my retinues only heavy infantry and archer.
Are you talking about retinue Camel Cavs or levy Camel Cavs? Retinue Camel Cavs are the standing army you recruit; levy Camel Cavs come from the cultural buildings you build in castle baronies. The former is great while the latter is not noteworthy.
Camel Cavs are one of the best retinues in the game, especially when you're facing strong opponents or far larger armies, but if you're just routing random scrubs when you already have far superior numerical advantage, then yes, a bunch of Light Cavalry can do the job better because you can rout more survivors and probably wipe an army in one shot. However, Pursue Phase is generally not as important as Skirmish Phase (the most important) or Melee Phase--if you can always defeat enemy armies when they're at full power, then what else is there to fear? You can easily chase down any smaller number of stragglers and survivors with broken morale, even if it takes three more battles to mop them all up. Sure, it can be a chore at times, but generals with Organizer traits should always be available in your army.
