Menelkir: I don't know about you guys, but the way i play this things, i always end up putting more emphasis in the last "X".
I have an unconscious habit when I play these games - I tend to be extremely friendly, offer alliances and technology left, right and centre (but usually either stuff that's worthless, or stuff that can't be used without a significant investment of resources - by which time they would have researched it themselves anyway) and I slowly build up an extreme defence in one quiet corner somewhere - I don't go out attacking but sit quietly behind a very powerful line of defence.
I land-grab when possible but avoid all confrontation in doing so. But once my empire is nicely running, I start massively increasing their defences - never attacking but just building up a front-line force so that people just think "that's not worth attacking yet". If anyone tries to steal territory from me, I have a tendency to stomp back hard with my entire forces, reclaim my territory and then leave it at that.
And behind closed doors I build up an one-time super-army with the latest tech (I've barely used any army or technology by this point at all) and then just swarm out and take the majority of the map in a short space of time (starting with whoever is already pissed off with me / has already attacked me).
I find myself doing this in MoO, Age of Empires, The Settlers, all those sorts of games. It doesn't always work, and it's heavily dependent on being able to provide a defence line quickly, but it seems to be "my" tactic whenever I play these games... much more of explore then shelter then assemble then exterminate.
The early alliances keep the major players off your doorstep (while everyone else, including your allies, fights among themselves) even if it costs you some tech (but let's be honest, by the end of
any game, everyone has all the tech they could ever want), you're not wasting huge resources on armies that just march off to die, you can build units of only one or two powerful types (not having to build every little enhanced design just to keep up) and because you are choosing the layout of your empire, you can easily stop yourself from over-reaching and leaving some narrow / back-of-field parts undefended. And then when you have a decent army, it's just a matter of fending off attacks on the frontline until you can build something big enough and powerful enough that it will just walk through the whole map capturing territory. At that point you start breaking alliances as they become untenable, and slowly removing everyone else one by one.