My first real try as Byzantines, took me 5-6 retries (starting in 1399) before not getting nerfed during the initial expansion.
Feel free to disregard fonts and my attempts at modding country names. I play with inflation turned off. (never could balance a budget)
Early on I got very lucky, the Ottomans was fighting the Timurids, had no allies besides Serbia and Bosnia and had been split up severly on the asian side in earlier fights. They had been in a recent fight with Castille, and had only 1 galley and 1 transport ship left.
I waited for the european Ottoman army to pass ... the Serbian army ... the Bosnian army ... and then brought out my 4 ships, blockaded the strait and annexed most of the european parts of the Ottomans using 4000 men. (2000 sieging and 2000 guys running around to where he was building armies)
After that it was just a question of picking the fights carefully not to cascade into fights with any major power. No reloads. No wars without CB.
I play as an extremely religious nation, taken all the NIs and descisions towards stricter religion, max narrowminded. No tolerence for heretics of heathens here, we burn our witches. Every time i manage to get a bunch of german minors against me, I try to smack as many as I can be bothered with firmly on the head and force-convert them. Hungary and Switzerland embraced the true faith completely after such conversions. (Since I have restored the Pentarchy, there is just one church anyway, people just need to be reminded.)
Recently (the current BB) I also conquered Mecca (took it from the french). I'm slowly working my way north through Italy, the aim is to take all of Italy and connect though Croatia. Also I plan to push Georgia (Sakartvelo) away from the Black Sea, making it my 'Mare Nostrum'. I still want to have them as a screen from the hordes though. Only alliance I have is with my orthodox brethren in Ethiopia, who I protect fiercly.
The four major powers in the world are me, France, Spain and Norway. England got very split up early on, every minor that can be formed on the island was there at one point or other. Denmark had holdings there, Scotland tried to take it over, but France has been the major power since forever.