Power attacks are your friend if you are planning to dual wield. The off hand power attack strikes very quickly and can break a guard or stagger an opponent when they are trying a power attack of their own. You can also cancel a normal strike into a power attack, which can lead to some devasating damage for a relatively cheap stamina cost. Generally speaking, off hand power attacks tend to come out faster and are easier to direct.
Also, the dual weapon power attack is extremely powerful but takes a heavy toll on your stamina. Still, it can be very useful, as it is your most damaging attack and tears through any defense your opponent might have. I am not sure how well known it is, but if you hold both attack buttons, release as the swings begin and then tap the attack buttons again you will do four normal strikes in rapid succession. This is useful against creatures and dragons, especially if you want to conserve stamina.
Dual wielding is a lot of fun, especially when you use footwork around enemies. Striking down a cave of bandits with flourish is extremely satisfiying.
