Being more effective with a faction means you have to know the strengths and weaknesses of the faction you play yourself and of your opponent.
Playing some singleplayer with a certain faction helps your knowledge or the individual units. (I've tried some factions myself for that purpose)

Some overall things when playing as the Germans is to remember most units lack good armour, which makes you vulnerable vs. archers. If possible try to deploy (and fight) in the woods. A lot of german units have wood bonus and missile units inflict a lot less casualties on your units when hiding between trees (I hate fighting in woods btw for lack of vision, so you might get an advantage from that too after some practice). Even when you have missile superiority hiding some units strategically can help a lot. Luring a unit or 2 who already fought a bit to a patch of trees and surprising them with a unit of fresh berserkers might rout them in seconds.

Berserkers are good, but they are weak vs readied phalanxes, heavy archer fire and horse archers. I generally don't take more than 2 (out of 20) when I'm against phalanx factions. Any other unit will take some beating, including elites like urban cohorts, armoured elephants and cataphracts.

Gothic cav is the best barbarian cav and they can match most faction's heavy cav. Every army should have some of these.

The infantry has 3 essential units imo.
The spear warband is the backbone of the army used to pin units you will then flank with any of your other units.
Night raiders will kill any lighter armoured unit, they are swift and instill fear.
Chosen axes are the real killers when against heavy armour.
A single unit of screeching women might be a good idea if you want to fill a cheap slot. Even the slightest morale penalty can tilt the scales in your favour.

The ratio night raiders/chosen axes should be based on what you expect. I'd get a lot of chosen axes against roman infantry for instance and some more night raiders against other barbarians.

Hopefully this will help you a bit to improve your game. If you want some more feedback on army composition you should give a little more detailed information about the exact money level. opponents factions and map you play.

The main thing to take into account when playing as Germans is the morale game. Your men are scary, and with some units to keep morale up. Your main aim is to scare your way to victory, then chase down the survivors.

Works for me.

Both of the guys above give great advice. I can add little to what they write, except to tailor your tactics to your style and the strengths of your units, while avoiding letting the opposing force exploit your own weaknesses.

I tend to found armies around Gothic Cavalry and Chosen archers, with a small group of speamen for the archers to hide behind. I also keep a unit of berzerkers behind the line- their very presense creates brown smudges in opposing soldiers' trousers and togas.

Gothic Cav is like a tank- use them to smash the enemy cavalry then bgin turning flanks. End game is they chase down the routers. Sometimes my spearmenr barely get into the fray...

Archers are used en masse- four bands in a group, then group-fire upon a single target. Real quickly that unit is reduced to shreds, then shift fire to the next. If things are getting hairy, put the zerks on a flank and let them do their thing.

id have to reinforce what the other guys have said. germania's main weapon is intimidation. there are only a few units in the game that will not run from berserkers. only a very few. but good luck, i have to say germania is my fav faction to use.

For the germans I like to use the "scare square" very simular to a noob squarr but use screeching woman and berskers in the square with some ranged. I leave mine open in the back in a basicly half cirle with cav on the wings. When enemy approces have the range use fire and ur women scheeching by the time they hit ur line of spear men there are scared sh##less have the, engage for a while drop the xerks and women into the line insta riout for almost all enemys espacily other barb civs

-edit- arty and cav heavy armys are very hard to beat this btw id change up for armies like that also need to be causious with ur cav. If you lose them you have,pretty much lost and its probly be a nasty lose too

[This message has been edited by Babyfaceroman (edited 10-13-2011 @ 03:20 PM).]