Since getting this game for me for Christmas, Julie has been nice enough to play several two-player games with me. I've pretty well settled into my overall strategic idea. The execution changes from game to game, in major ways that I wouldn't definitely call strategic, but the main idea is this:

Products are king.

Previously, most of my plays of this game were with five players. Almost all goods shipped were shipped on the boat worth 2 points. By the time a boat got to the 3 slot, if it ever did, it had maybe one space left. It wasn't really worth using an action most of the time to get just the 3 points.

In a two-player game, there are just as many boats, but less capacity for growing products. The result is that we usually ship on the 3-point boat. This makes shipping the dominant concern. In a five-player game, shipping is one of many viable strategies. You can win without ever shipping anything.

There are two things you can ship: products and goods.

In a five-player game, it's good to be able to generate some goods if you're planning on making shipping a major part of your strategy. Even on the 2-point boat, there's a lot of contention and the spots for the easy-to-produce products. If you're not agile, you won't get those spots. If you're the only one with a rum Distillery or Cigar Factory, on the other hand, you have a near-monopoly. Often you can take it easy and still get the spots on the 2-point boat. If you work a little bit harder you might even manage to stall until you ship on the 3-point boat.

On the other hand, in a 2-player game, there's often little incentive to make goods. Most boats have at least 60% product slots. Some boats have 100% product slots. You can stay ahead of your opponent even if you just focus on dominating the product slots and ignore the goods slots entirely.

The most critical building to this strategy is the Dam. You want to maximize your output of products. There are spaces on the board that align with four products. You often want to take those spaces, and use 2 water to produce all four. The Dam keeps up your supply of water nicely.

The next most important strategic consideration is what to do with all those products. It's great to produce four products in a turn, but unless you do something with them, they'll rot at the end of the turn. Of course sometimes you intend to ship them with the Mayor. However, it's better to have your products lined up to ship in your warehouse the turn before the ship reaches the 3 slot. Otherwise, your opponent might get the jump on you and ship before you. The Tradeswoman is an outlet for your goods that's always available, but often pretty weak and sometimes very weak if the supply-increasing Market Act is or has been in effect.

The remaining ways of disposing of your products involve buildings. One building, the Warehouse, you start the game with. Storing your products allows you to use them at the opportune time. However, the Warehouse doesn't align with the best places to put your Worker to generate products. If you have other buildings that you want to use every turn, you won't be able to use the Warehouse.

I suggest buying some other building that makes use of products. You can alternate between the use of this building and your Warehouse. For example, you could place this building in the bottom right corner (4,3), and place two buildings you want to use every turn at (2,1) and (3,3). Then you can alternate between placing your worker at (3,1) using your Warehouse and two others, and placing at (2,3), using all of your buildings except the Warehouse. This gives you some flexibility to Work for different resources and products as tactically necessary, while still generating a lot of products without letting them go to waste.

The Distillery and Cigar Factory are two candidates for this building. You use them mainly to preserve your products, rather than with any specific use of the good in mind. Eventually a ship will probably come along demanding that good, and that gives you an extra couple slots to fill while you're already shipping a lot of products. Or, you can just sell the good using the Tradeswoman if you need some quick cash.

Building a second Warehouse might be good, although I haven't tried it yet. It doesn't give you any additional capabilities, but it gives you flexibility in where you place the Worker while poising products for a quick ship or other flexible use.

The Product House is good, although limited, because it only lets you convert 1 product to money. You might want to combine it with another of these options.

The Monastery might be good. It converts products directly to victory points. I haven't tried it yet.

Late in the game, a Golf Course is a natural build. Although I think using your water to generate extra products is a better path to victory, with the Dam even despite your best efforts you might not be able to use all your water for making products. The leftover easily buys the Golf Course and then turns your remaining water into points in one or two turns.