Pros
-High Mobility
-High Burst
-Strong aoe
-Great ad scaling shield
-play making champion
-easily snowballs

Cons
-low base health regen
-hard to come back once behind
-full ad
-combo based
-no sustain
-takes lots of time to master
-weak to cc

This is the one thing that drastically separates a REALLY GOOD riven between a BAD one. Animation canceling is the core of being a good riven. The most common riven combo is the "fast combo." There are lots of combos for riven and you can watch boxbox's video on this as it is very hard to explain.

Generally if your against a ranged champion you want to e in and q out after you kill a minion unless your under tower. If your against someone that beats you in lane you should start with wolves/raptors, recall buy potions and a ward then tp back to lane.