Its kinda hard to decribe but you need to assume some role playing elements.War is not banned or anything,but you need to be selective.You would like to follow real world situations.Like a gradual build up of hostilities.Perhaps a severing of diplomatic relations after an international incident(tech theft,sabotage,infringing on borders etc).
At the same time you would make efforts to sway world (other players) opinion and forge agreements and alliances.Stuff like ceding of a city for a base of operations or a worldwide trade embargo..all kinds of stuff.
It takes a certain degree of,for lack of a better term."co-operation" in your play style.You don't want to hog all the wonders or land.Basically,you want all players to stay interested for a long time.This requires balance.Many players are not well suited to this.It means you or someone else may need to "back off" to avoid the snowball down a hill effect that happens in many mp games.
Many dip games have set rules about attack and what not.Like a 1 turn warning.I think this is severe but I get the idea why.
Your true goal should be to play to a finish before trying to win.