I seem not to being able to edit above post, sorry for that long link that I wasn't inteding to put there

I usually pick on the weak civs - the ones that for whatever reason lost out in the colony race. They're usually way behind on tech, and their homeworlds are going to be valuable.

I don't declare war that often. I just construct a military starbase with all the ship boosting bonuses right next to their homeworld and stockpile the necessary ships and transports. Almost invariably they'll trigger the war, even if it is suicidal. If they don't, I get to attack when I'm ready - which means a civ that never pread beyond a couple of systems will probably die in one turn. Avoids any irritating surrenders. Strangely I often seem to get the "We can see those transports" war triggered the turn after I've declared war. Always feel the enemy isn't quite up to speed there - in extreme cases it looks like they've managed not to notice I've already conquered them.

I goofed another one !

I did not pay too much attention to the races selected since I am still learning the GalCiv universe. now the following happened:

I play Arcaean and I selected the game mode where only military victory works (no tech or aliied/influence allowed). I am in a position to murder anyone and have gobbled up humans (hate them anyways) Yor and 2 minor civs.

The Torians and another civ were my allies until I was sure I could win - then I took down the other civ (break alliance, attack, win as I expected). Now I am allied with the Torians and probably since we are "team" from day 1 I can't cancel the alliance. Either I am too dumb to find the button - it is not where it was for other Civs - or it wasn't intended.

Since the only Victory condition left is "last man standing" I probably shouldn't have picked Torians for my Galaxy. Now the only course of action I can imagine is to grab planets by flooding them with influence bases.

Is there a way to break up Alliances pre-determined by race choice ? If not, it seems odd that I did not "win" considering only me and my eternal Ally are left....

On a Gigantic map I have been able to buy out my last opponent's empire (I don't remember the exact number of planet but it must have been quite a few) only because I had ridiculous amounts of money from a tourism mega-event.

I'm not afraid to fight the strong guys at all, if that's who my neighbor is.  It's hard to bribe other civs to attack them, so I'll just do it myself.  Just being at war forces them to focus more on military rather than extending their lead.  Since all his ships tend to come at you from one direction, just get a military starbase and fleet up.   I'm not terribly worried about all the other civs--just a few bribes, and they're all at war, too.  What's gorgeous about fighting strong civs is, the tech stealing.  So, your military advisors insist on not trading us Harpoon?  That's fine....  Weak civs don't have anything I want.

I also need to spy around and see what planets I want.  If I see a precursor library, that may well decide who
I want to fight.

I generally look for someone who I have a sizeable height advantage over, and who appears to have realtivly low upper body strength.

Yeah, I often bribe the strong guy to attack somebody else, and then I turn around and attack him while he's still at war.   I have to pull my spies from his planets, though--he'll use the money I just paid him to nullify my agents.  I need those guys to nullify his morale buildings ahead of an invasion.  No matter--I just care about getting Medium or High espionage level, so I can track his ships.