Although I'm not quite sure where it'd be best to start as both directions have their merit and result in a larger border I have one Tip for you that applies to both situations:
Amphibic RAID!!!!
get a small fleet a medium sized army and attack their training centers when their armies are marching for your borders, this will give you some time (now they will spam Cheap units instead) and money to support expansionist plans.
Always destroy government and Barracks,
wonders If you play that way
and everything else if you don't plan on capturing the settlement the next ten(random number) years.
The ptollies and the Greeks will suffer quite a bit from these actions, sadly the Selucids take some more commitment to cripple.
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