Heck, nothing too fancy on this side.
Start by doing workers (whatever unit gathers resources) and building whatever to get ready to produce your first military units (unless I'm playing Norsemen, their first units are too weak, so I move on to the next military building ASAP
).
Produce about two to four times more ranged units than mellee. Use the melle basically as human (or whatever they are) shields for the ranged units.
And then I overdo on this type of basic units...
Really... nothing beats
numbers of cheap infantry!
I'll gladly add up a few more advanced units, criteriously chosen (including all the buildings and upgrades needed to start producing them) depending on my foe (and obviously my choices).
This reminds me, regarding the Dwarves, it takes a while til you get to the point you can produce a ranged unit which I think is an interesting way of balancing out a faction (wciow's credit).
But my other strategy of producing more ranged than melle units kind of gets scr**d at the begining.
When playing Magic, as said earlier, rushing on your enemy is the key. Battlemages work great for that (they're fast and ranged). Daemon I just use to draw the attention of the enemy. Ghost armors is what I use for erm ghost shields.
And battlemages for what they cost can beat the equivalent amount of dragons you produce. Well... kind of...
Archmages, yes, I think are mostly annoying.
(I second ultifd on your nickname, Archmage!
). Though I might use some in specific cases.
If I'm stretched thin across the map, I'll bet on the fast units as well as the flying ones.
For most factions other than Magic, I'll be expansionist like Omega described.
Oh, I'll be rushing if playing the Elves too (well, a very long time since i played them, I think it was still 0.8!
).
When facing multiple enemy players, I'll be happy to disable a base amd move on rather than completely destroying it.
If I have allies, I'll most often help them in an unusual way. If they're attacked, I'll rarely send troops to defend them, I'll attack the bases of my ally's attackers instead - works like a charm!