The fatal glitch is a glitch that occurs when playing multiplayer. (hotseat, single card, multicard) when your name is less than 4 letters long. I know about this, because my username was Sam and happeneded to me. It basically freezses your game permanently and/or deletes all game data. IT stinks horribly. So remember to make your name 4 or more characters long.

Use Spearmen/pikemen against Enemy Cavlary.
Use Siege units to destroy enemy Buildings quicker (The Scorpians Won't Work).
Put Ranged units on the mountains,This gives them more defence and a better range.
Horses should attack on plains and camels should attack on desert because they both get a attack bonus.
Build Towers so your buildings get more defence.

These are very useful.