I often get ganged up on in MP's:-
Playing MA Man - MA Arco/MA Ermor/MA Pangaea ganged me.
Playing EA Atlantis - EA T'ien C'hi/EA R'lyeh/EA Agartha ganged me.
Playing MA Ermor - MA Abysia/MA Mictlan/MA Marignon ganged me.
Playing EA Niefelheim - EA Sauromatia/EA Abysia ganged me.
Playing EA Marverni - EA Nielfelheim/EA Abysia/EA R'lyeh ganged me.
Playing MA Agartha - MA Bander Log/MA Pythium ganged me.
Playing LA Mictlan - LA Atlantis/LA Abysia ganged me.
Playing LA Agartha - LA Mictlan/LA Ulm/LA C'tis/LA Ermor all ganged me and I still won!
etc, etc, etc....
So, I know alot about being ganged up on. Why is this happening? Because (in my opinion) of the following:-
1) I am loud. By this I mean I am a regular contributor to the forum and usually the game thread. So I am noticable, making myself a target.
2) Have (usually) a strong early game, so I take the lead on most graphs.
3) I am inclined to be aggressive, especially if I detect any weakness in my neighbours. Other players take advantage, wait till I am exhausting myself in a war then attack.
4) I love casting forge of ancients!
The no.1 best thing you can have in a MP is a loyal ally who will stick with you to the very end in the late game. So far I have found 95/100 dominions players to be power mad, stick the knife in soon as look at you. A trustworthy ally is as rare as gold dust.
Btw I have offered a pact to lots of different players, of complete alliance until the end of the game where just the 2 of us have been left. I have never had it accepted, not once in nearly 20 MP games. Why I have no idea, surely finishing in the final 2 with 50% chance of winning is a good deal?
So avoid those if you want to survive...however I will have a more exciting game then you.