(Medium map, random 6 AI at challenging, no tech trading)
Just sharing...
I tried a whole new approach to the game the other day and set up a custom race to use influence, as much influence as I could lay my hands on through race ability and party choice.

My main theory was that by removing points from Economy and Trade, I could assign them to Influence and not be in trouble financially because more Influence means more tourism bc's. Most theories have holes...

The start was a mixed bag; the home planet was not much to sing about but there were plenty of colonies to grab nearby. I still kept up military strength but since I didnt intend to take part in any fighting it was purely for show. I just wanted to look strong. This gave me the opertunity to build ships with 5/0 laser dmg as my first small hull (no drives). 12 of these meant I was top of the pile for a while. But it was all pure posturing.

Then it started happening. 3 planets defected to my custom race before I even had planetary invasion. Because the home planet couldnt churn out colony ships very fast at the start, I 'shared' some systems with other races. This changed quickly as I developed my planets.

I occupied a strip of space down the middle right side of the map that separated the AI races - a worrying position. This is where my points spent on Influence really kicked in. The other races went to war and every planet the AI invaded near my border came swiftly under my control. Their wars cost them a fortune in resources and I reaped all the rewards!

I was gearing up to deploy Influence starbases when a random event made a whole heap of 0 planets turn class 5. I grabed all but 2 of them (about 18). The boost to my Influence in that territory spelled the end for the terrans and a number of torian planets. Of course the Yor were having none of it but it was too late. With 2 keenly placed Inf.Starbases I covered over 75% and won.

So, not a single shot fired, no wars entered into or started, no Alliances made or particular diplomatic ability persued. I used posturing to maintain relations and avoid conflict. The success of Influence at the beginning was startling but not economically. Although my attempts at posturing paid off literally in tributes!