I was very sucessful with the following strategy:
First thing to do is moving the capital to Seleukeia and build roads and foreign MICs everywhere. With your starting troops and a few additional Pantodopoi Phalangitai you can kick out the Ptolemaoi out of Asia Minor and the Phoenician provinces till 270. They will take a while to recover, you may even be able to take Alexandreia and Memphis.
I took Baktra as soon as I could, this crippled the Baktrians and broke their alliance with Pahlava. I also destroyed Pontos very early, so I had a lot of time to conquer Asia Minor. Of course it might be more fun to fight these factions later on, but I deceided to go the easy way here...

You'll also find some usefull AS-tips in this thread:
https://forums.totalwar.org/vb/showthread.php?t=79867