9. Establish Some Interconnectivity Between Seasons
Sometimes we feel like we remember the events of seasons past better than the actual characters. For instance, when Quinn (Desmond Harrington) is about to sleep with a murder investigation's person-of-interest, why wouldn't someone point out to him that one of his girlfriends was in league with one of the past season's villains? Why would Dexter leave Jamie (Aimee Garcia) and baby Harrison in his house even though he knows Travis has his wallet and keys? Does he remember how that turned out for Rita (Julie Benz)? Better question: Does anyone on this show actually remember Rita?
The list could go on and on. You could watch this season and never know that LaGuerta (Lauren Velez) and Batista (David Zayas) were married, or that Quinn knows Dexter murdered Peter Weller's character just last season. At the rate that this show forgets its own history, we wouldn't be surprised if next season begins with Dexter quickly tranquilizing Deb (Jennifer Carpenter), after she catches him killing Travis in his ritualistic manner, and her waking up thinking she had one beer too many.