The Turks have a well documented guide back from original MTW days. Approaches like the attacking the Egyptians and ransoming their leader are well known. As I am currently playing a XL early hard Turkish campaign, I thought I would post a few thoughts on how it was going with a particular view on how XL was impacting on the game as a whole.
Starting between the Byzantines and the Egyptians, you have to be aggressive from day 1 and decide which way to go with a view of weakening or even knocking out one of your 2 powerful neighbours. With rich pickings to the south and multi star generals with Katanks to the west, it is obvious to attack the Egyptians. I gathered all I could together and took Syria and Antioch quite quickly - I think I got a ransom as well. I built like crazy and took Armenia too. In Armenia I built an inn and this over the next 30 years was a good source of mercs - as you have to grow quick to survive, mercs are a real godsend. I grabed everything that was available, even things like spears and UM.
In XL taking Armenia means sorting out the Armenians. They have some tough troops, but it can be done quite easily by weight of numbers. That is one lesson to learn with the Turks - you are going to loose lots of men - so keep replacing them as soon as poss. Armenia and Rum are your sources of quality troops until you grow a bit so make sure they are OK. One mistake I made was not bribing Georgia early on - the Byzantines beat me to it.
During these early moves, the Byzantines were quiet - we were even allied for a few moves.
Once you have subdued the Egyptians, it is time to sort out the Byzantines - I had even lost Anatolia to bribery to the Byzantines. After a short pause for regrouping I launched the assault against the Byzantines. After a series of clashes, I arrived on the plains before Constantinopole. Instead of assaulting it immediately, I just kept reinforcing the beseigers while they threw all they could at me to lift the seige. This series of battles meant my army grew in valour and command stars while the Byzantines were worn down attacking me. After a few years of this I walked into Constantinopole. It also had the added bonus of putting the Byzantine royal family - and not much else on Cyprus. I rumaged up a force from the easten med, invaded and wiped out an emperor and a few hiers in one shot. Sadly no ransom - I assume no money left - but it left a neutered Byzantine bottled up on Rhodes.
XL brings a couple of things that MTW/VI doesn't - that is a wider collection of foes and money problems. The new factions - Armenians, Cumans, Serbs etc - make for a richer, more varied game. If you had a bit more money, you could even pick up some nice troops with a bribe or 2. The downgrading of trade and general costs mean you are always short of money. The odd ransom helps as does looting etc, but be prepared for a lot of insufficent funds - a bit galling as you can get them at the same time as the "you are the richest faction" messages. In the past I have paniced about these, but with the Turks there is only one approach - keep on pushing. The quick way to money is conquest - but make sure the target is a rich province not a poor one. Be prepared to loose a couple of provinces occasionaly and don't worry too much unless they high earners. The lost province allows for the other weapon in your armoury - the Jihad. I always try to have a marker handy - I build them in Rum - as they give an instant army at an excellent value.
As for troop types - there has been masses written about the types available. I concentrate on Saracen infantry, desert archers, armenian heavies, turcopoles, camels and horse archers. The Murabatin cavalry in Egypt are nice when you take it.Also units like the Ghazi infantry are fun. However just as important are the bulk standard spears, archers and UMs as you need to garrison a lot of provinces. I have mentioned mercs above, but they are important - buy them when you see them, especially good infantry - Italians, Russ armoured spears etc. Finally I made the odd emissary to use as eyes in people's provinces as well as diplomacy, alims for zeal to help the Jihads and when you have Syria Assasins. The Byzantines put all their court on Rhodes - loads of emissaries and princesses - so this has become the assasins training ground!!
Well - that's about all for now - feel free to add your thoughts. Next up I will report back on the next phase - consolidation, expansion into Europe and the Steppes and the arrival of the first Crusades.