The coming update has trains and factories! The game is mainly about managing compounding growth with discrete losses (having more land and cities increases you population cap, and your population follows a logistic curve, so you want to reserve an amount of population to maintain growth, and it's programmed so that you want to use a discrete amount for attacking instead of a constant trickle)

A good strategy that works well for me is to prioritize moneymaking and win by cleaning up a nuclear wasteland. Some tips for that strategy aka trademaxxing:

* The fastest way to make money is to get lots of ports and ally with people near and far. Boats give you more gold depending on their distance traveled

* Set up turtled-in bases on islands and have warships patrolling near them to shoot down potential land invasions. This combined with your small land area will make it less appealing for the big countries to focus on you

* Once you have enough funds for a MIRV, maintain strategic deterrence by having multiple missile silos - so you can launch the MIRVs any time

* Continue to trademaxx and wait for the big countries to nuke each other into oblivion

* Once the time is right (and you have enough funds for multiple MIRVs), move in to clean up the nuclear wasteland. Get some cities but don't spend too much money. If another country starts attacking you at this point, you can MIRV them again. You are also much more resistant to MIRVs since your assets are in money instead of structures and can rebuild quickly