Well i did serval CK games before, have played England, Leon, Apulia and did very well.
Now i tried to play Byzantine but after several games, i donot know waht to do.
The empire die always in civil wars.
Does anyone have some advise for me?
Change Ruling law to Feudal Contract. I believe Byz start with Royal Prerogatory, which is bad, and the vassals hate it.
Settle peace with the Seljuk Turks ASAP.
Then get your vassals straighten out. Get rid of the rebellious ones if possible. Just be careful about too much BadBoy.
Don't worry if a few leave your realm. You can always get them back.
... and since your starting rulers suuuuuck ... get the best Chancellor you can get your hands on.
Once you get things settled, consider switching inheritance law away from Elective law, or one unanticipated death could loose you most (or all) of your power.