As egypt you should take constantinopel and georgia as soon as possilble, then youll have the msot defessnsible empire ever, just make sure to get ships to protect against back door invasions. And put like 2 armies in georgia to protect against horde. Then build up and tech up. After this youu can build up your army and take over europe without ever having to resupply your units if you build enough. Also build lots of jihads, you can launch multiple jihads at provinces. Then invade any easy provinces even if thyell get taken right back, so you can send jihads there way and get free nizaries and kwarzmian which seem to show up a lot in jihads in early game.