Seleucid Problems

[Nelson]

Yup, what Dutch said. Hold the other fronts until you take Egypt. Then develop your ports and the let the money flow in. Before long you can build balanced armies that have no significant weaknesses.

The world will be your oyster.

[Conqueror]

In the beginning spy the Parthian city to the east of Seleucia. They usually march most of the garrison out to the deserts. Have your army close to the border and wait for an opportunity. If you time your attack right, you'll be able to assault the city when their army is still a turn's move away and can't relieve the seige. Exterminate or enslave the population (enslavement could be used to boost Antioch toward the next city size) and destroy all the buildings. Then abandon the city save for a minimal garrison. Even if the Parthians retake it, they won't be able to use that city for anything useful for a long time to come.

Then go on full defensive in north & east while you focus on your southern offensive against the egyptians.

[GeneralHankerchief]

Generally you should go for the richer enemies first when playing as the Seleucids. That means Egypt, Pontus, then Parthia/Armenia in that order. It's just a lucky coincidence that this is the same order of threat they pose to you.

Once the Nile and Turkey are yours, it doesn't matter how teched up Parthia and Armenia are, your wealth will always beat them. From there, it's onto Greece, then Rome!