Choosing the proper tribe is crucial when playing AOE. Obviously, you should stick with a tribe that allows you to build units you're comfortable working with. It is very frustrating when you pick the wrong tribe; you'll play out a game only to notice that you cannot build a specific unit or to see that the only units with advantages are the ones you don't know how to use. You should not only consider your own style of playing but also your allies' and opponents' style of playing. For example, if you know you're opponents love acadamy units, you should pick a tribe with archer advantages such as Assyrian. Or if your ally really likes a certain tribe but it doesn't have good defense options, you may want to play Babylonian and fill in some defenses for your ally.

Use the following as a quick reference when picking a tribe :

Best Tribes for Rushing : Assyrian and Shang.

Best Tribes for FFAs (Free For All Games.) : Babylonian and Egyptian.

Best Bronze Age Tribes : Assyrian and Egyptian.

Best Tribes for Archers : Minoan and Assyrian.

Best Tribes for Elephants : Persian and Phoenician.

Best Tribe for Acadamy Units : Greek.

Best Tribe for Calvary : Yamato.

Best Tribe for Defense : Babylonian.

Best Tribes for Priests : Choson and Egyptian.

Best Tribes for Siege Weapons : Sumerian and Hittite.

Best Tribes for Water : Minoan, Phoenician, Greek.