This is a big topic that you are opening. The thing is that micro isnt that important on aom(like it is on wc3 for example).
Anyway, here i go(you owe me big time for writing all these down). First of all, with double click you can select all similar units(all hoplites for example) in the screen. With ctrl+double click you can select all similar units that do the same thing(all moving hoplites or all standing idle hoplites or all woodcutters). Since units usually die/created fast, i dont advise you to assign numbers on squads. I usually assign numbers only on my raiding squads, special units(soo, nidhogg, titan) or sometimes even on my seige units. So you will be doing the selecting mostly with double clicking.
First of all, formations are close to useless(maybe except for alt+x for when scouting with raiders). Stances are nice, use alt+s on units like soo or alt+d or alt+s when you dont want your units to get lured from enemy units(although i would advise you to manually hold your units back, cause if you forget alt+s on some units, they wont be doing much till you change it to alt+a or at least alt+d).
When you want to just charge in the enemy, just use a+click which is "move and attack everything on sight". Also use "q" which is the stop button when you see that your units are stupidly following something that they shouldnt.
And now lets go down to some basic military tactics. Obviously if you have spearmen+slinger and you are against tox+hippikon, you want your slingers to attack enemy tox(and your spearmen to attack your hippikon, but this becomes automatically since hippikon are usually on the front). 1 way to do this is by selecting your slingers and then shift+clicking on all toxotes, 1 by 1. This way your slingers will snipe 1 enemy tox at a time. This most of the time isnt good, cause sometimes it gets messed up and your slingers will move towards the tox instead of hitting. Your best bet is to select your slinger and then manually aim 1 tox. Then aim some other tox(once the first tox is dead), etc.
Now lets assume you have the hippikon+toxotes army and you are against slinger+spearmen. If you just charge in, your hippikon will attack enemy spearmen which isnt the best thing to attack with hippikon. So instead of just charge in, you send your hippikon to the side and around enemy spearmen and you try to flank enemy slingers. Once your hippikon get next to enemy slingers, press q to stop them.
Also they are some lure technics. For example, you send in some units(preferrably fast ones), and once those units get close to some enemy units, you run back again. The enemy units(which are most likely on alt+a) will follow your units to their death. Same thing applies for luring units close to your tc/castle/tower fire. Generally try to fight on your own terms and on ground that favors you(close to your production buildings and your arrow shooting buildings).
A nice way to lure units is with your ranged units. Select them, get them on the front, and start hitting enemy units. Lets say for example that you have spearmen+slinger combo, send slingers in front and start taking a few hits at the enemy hippikons. Once those hippikon start moving towards your slingers, draw your slingers back and send your spearmen in.
1 other cool thing to do is to garisson(alt+click). Lets say that you have 8 chariots next to a midgol of yours. And enemy sends some hippikon there. Instead of just letting your chariots die to enemy hippikon or running(thus losing the midgol), garisson your chariots inside the midgol and ungarisson them from the opposite site where the hippikon are. Take a few easy shots at the hippikon and when the hippikon move towards your chariots, garisson your chariots inside the midgol again and ungarisson them from the other side(whichever side is further from the enemy hippikon). Keep repeating this till hippikon are dead. Works better if you make couple camels though . Same cool trick works on your tcs under attack. Say that you have 10 villagers gathering wood next to a tc. Enemy attacks your tc and then you garisson your villagers inside the tc(to save them from dieing). While your enemy is attacking your tc from 1 side, ungarisson the villagers from the other side and mass repair the tc. If enemy units go after your villagers, garisson the villagers again and ungarisson them from the other side(the most safe side). Also make sure you kill enemy sieige with your villagers(if its melee seige at least) by using the same trick(ungarisson the villagers next to the seige, kill it and then go back inside the tc).
All these are very advanced tactics for aom and they arent that important. The most important thing is not to fight battles you cant win(retreat), try to lure enemy units close to your arrow shooting buildings(and generally fight whenever the chances favor you) and try to keep your units from getting lured(press q or select them and get them back). There are probably more tricks that i am forgetting now but dont worry aom isnt about micro.
[This message has been edited by NIB (edited 06-22-2004 @ 11:37 PM).]