I prefer safety in numbers (trade level or not). In one GC, my country of Prussia has a pretty huge chunk of the Baltic coastline, a solid line of provinces from what used to be the continental part of Denmark to Novgorod. I get 12 traders/year (the maximum). I own 3 COT's. Most of the time I have 3 total monopolies. Occasionally some puny country sends a merchant in, but they get kicked out quickly. The key to Monopoly is banning trade to your biggest foes (Sweden, Denmark, Russia). They hate you anyway cuz you stole the COT's from the in the first place, and a quick war can get you some quick provinces/dollars.
On the other hand, in this particular game, I focused too much on economic might and let my armies degrade to crap. Russia and Denmark then proceeded to gangbang my lilly ass so bad that I said it was all over.
[This message has been edited by driedcow (edited 18-12-2000).]