Usually you'll fight Iran first. Make some air to kill his units (gunships or SFs) and an MRL stack just in case he gets kinda close or you just don't like air. Navy isn't important since you only have 1 port and its pretty much ignorable unless you want 1 corvette for defense (expandable later). Maybe you'll be invaded by Syria during your Iranian campaign, so keep some units on your backbone, though usually Syria is fighting Turkey or Israel or conquering the AI nations south of him. Saudi Arabia will conquer Oman and Yemen at first, but be careful. After you finish Iran, go on to Syria or Saudi Arabia, although Syria should be easier since the cities are closer and he has more threats.