macAilpin: When I first played the game, I would get all six buildings up, hire the specialists early, and would avoid expenses like Ports early on. And lost.
I started only hiring a Miner early on and worked to get my buildings up to 4x4 to get the extra flow of partially finished goods. Started doing better but still not happy.
Then I built only the finished product buildings in the first round, this allowed me to build three ships for goods, and build ports early on to move raw goods in ASAP. The extra shipping space allowed me during the first several round to purchase semi-finished goods and turn them around for $. When I purchased planks, I finished up the City Construction. When I started getting in raw material from my own territory, I switch my purchases from semi-finished goods to raw goods to try to get Minor nations. One or two Ship of the Lines, then up the buildings to 8 x 8 for the extra finished goods. I started out with a second Prospector to map out the resources quickly. When I knew enough, I would send them back (usually a switch to a Miner but only when my railway station was nearby).
This last strategy seems to work best. But any suggestions?

thedkm: I think your strategy is good, but you make two mistakes:
Never buy semi-finished or finished products but only basic products such as iron ore, timber etc., this is far too expensive at the beginning of the game.
Don't scatter your two Prospectors but send them to small countries ( by creating an embassy) to find resources that you will buy with your Developer.
if you want more information I have put online some chapters of the official strategy guide (I mean the scans), everything is very well detailed.
https://mega.nz/#F!XvgzBCpK!2JhBD0QHZXMtMXTk2XAcRA I end up making money in turning semi-finished products to finished products at the beginning because finished products get their best prices at the beginning. But that last only about five turns. Then I return to the raw material market. But to make this work you need 16 cargo capacity from the get go. Doing it this way has allowed me to get to 4 and 4 industrial capacity in all three markets more quickly than I have ever before. But I still can't get to 8 and 8 quickly enough.
As for prospectors, I use them early to map out my land quickly. This has allowed me to avoid missing resources due to the train station on adjacent parcels problem. Then when I know what my mining situation looks like, I turn one into a miner.
When know which Minor nation likes me, I'll give you suggestion a try.
(I will leave up that I originally wrote best price. That's not correct though. But I get a good price.)