Strategically, HOW do you play the slow game

[Zenicetus]

The one major tip I have to offer, is to play on Medium instead of H or VH campaign difficulty. Apparently (see other posts here), this normalizes your relations with other factions towards neutral a little bit every turn, if you're not doing something to upset them... like blockading ports or taking their provinces. Sinking ships seems to be immune to degrading relations, which is interesting (and useful).

Hard and Very Hard normalizes towards worse relations every turn, unless you bribe everyone to boost relations. In other words, you'll be constantly at war. It looks like CA substituted relations degradation for economic boosts for AI factions, on the harder settings. At Medium, it's MUCH easier to keep your neighbors at bay with strong border defenses like garrisoned cities or big standing armies near your frontiers.

For example, in my Spanish campaign I really didn't want war with France because I was busy elsewhere. They started a war anyway, I took their closest two provinces but didn't do anything else.... just garrisoned them and kept two big standing armies there. They sent several probes over the border, I killed them, but relations kept slowly improving every turn until they finally accepted a cease fire. If I had kept expanding and taking their cities, relations would have worsened. That's okay for blitz/steamroller expansion, but not if you're trying to maintain a static border with a neighbor.

This is different from RTW, where war was a binary condition -- on, or off. In M2TW, there are degrees of hostility in faction relations, and you can improve relations even while at war, if it's a war you don't want at the moment. I think this is affected by which side of a shared border the combat occurs... but I'm not 100% sure. At any rate, it's a lot easier at Medium difficulty. Otherwise you're likely to be constantly at war with someone.

(Edit): amending that last sentence: Of course you can't win this game or build an empire without warfare. What I meant is that Medium campaign difficulty makes it a little easier to choose WHO you're going to be at war with.