Dissidia:
Learn to dodge cancel. After doing specific attacks, immediately dodge (any type) to cancel out cool down animations. Doing this allows to combo set ups with brave attacks. Dodge canceling in one of the most important things to know.
If you are Ex-Death, learn dummy guarding/RP cancel. As soon as you are about to teleport with reverse polarity, immediately put up high guard after teleporting. This is RP canceling and this sets up a dummy block which, if you are good enough, is a great mind game. You can immediately perform another block or attack instantly after dropping that first guard.
Cecils search light attack can be chained into paladin force regardless of distance. When search light connects, immediately perform paladin force and you will hit the opponent regardless of how far away they are.
The Emporers Flares can be reflaceted back at him. All characters have an ability to reflect his Flare. Oh and StarFall is the greatest taunt ever.
uh..I'll think of more later.