Poland isn't a civ that has an implicit strategy. There's no risk/reward proposition, just some freebies. Do whatever you please--wide, tall, science, culture, domination, trade, whatever looks appealling at the time. Because of this, they're one of the easier civ's around. Try playing them on a higher difficulty than you normally would.
One thing I've done with Poland that worked well was to open both tradition and liberty early. Tradition to get the big culture boost from opening it, then move over to liberty for workers, settlers, pyramids, etc. Finish liberty then move back to tradition and take legalism after you already have 4 cities with monuments, and you can get 4 free amphitheatres.