Beware; I was playing fast and loose last night. Russia was 10 techs ahead and had battleships vs my frigates.
Anyway, I was buying all the CS away from her while I made a proposal to embargo Russia. I kept an CS ally on my border and I MoV'd a CS on her border, giving us a shared border. Next thing you know, I get a triple DoW and she bought out the ally that was on my border...
The other thing I did was take over Willem's land first thing with a c-bow attack. I'm not sure that was the best move, at least with Venice. They need the first part of the game to get alll routes up and running.