6. Borrow Heavily From The Comic Books....
Arrow has borrowed heavily from the Arrow mythos, staying pretty loyal Green Arrows origin, while also fleshing it out for a longer story. They've also made liberal use of characters, from heavyweights like Deathstroke and Black Canary to originally minor ones like China White and Walter Steele. If Gotham is going from the Gotham Central, there are plenty of interesting characters that could work. Renee Montoya and Harvey Bullock are already reasonably well known thanks to appearances on Batman animated shows. But how about Crispus Allen, Maggie Sawyer and Marcus Driver, all fleshed out characters with interesting character arcs in the comics.