-Wait until the "Guardians of The Galaxy" movie is released and take notes if it's a good film and also a commercial success.
-Call the new movie "Green Lantern Corps" instead of "Green Lantern 2".
-Find a good director with experience on VFX, with a great visual style and with remarkable storytelling skills. Campbell has done great movies ("Casino Royale", "Goldeneye"), but needed a better script, so find a good writer that knows the characters and its mythology, just don't bother to start filming until a great script has been written. The visuals and designs in the first movie were good, specially for the lanterns, the guardians and all the stuff related to Oa, it could have been much better with an improved script imo.
-Place most of the movie in space and other planets instead of focusing the threats/story on Earth.
-Recast if necessary like "The Incredible Hulk" did without needing a reboot. Reynolds was ok, the rest was kind of forgettable except for Strong that was a great casting choice for Sinestro imo. Maybe they could keep the cast for the lanterns (cgi based ones included) since we would barely see Ferris and the rest of Earth's cast, but I would understand if the producers wanted to avoid all connections to the previous film and start fresh after "Man of Steel", with the new movie belonging to the same universe of the new Superman movie and being different to the universe of Reynolds' film.
-A new origin story is unnecessary, start the film with Jordan being a respected member of the lanterns already, with maybe a couple of hints to how he got the ring (maybe Sinestro could mention how he thinks that Abin Sur was a superior lantern or something like that, without needing a flashback, just intelligent hints here and there).
-Make it funny (or not excessively dramatic and boring), but much more serious than the previous one, this shouldn't be a pseudocomedy. Make it closer to "First Flight" than to the previous feature film.
-The Green Lanterns Corps are like cool jedis, the cops of the universe. Many of them are misteriously dying or dissapearing. The guardians and lanterns somehow eventually find out that Sinestro has betrayed them and is using the yellow energy to form his own army with the rings of the murdered lanterns that have been turned into yellow rings through his own yellow battery built by himself or by the weaponers of Qwad, something similar to "First Flight" but with more Yellow Lanterns, with a huge final battle of Green Lantern Corps vs Yellow Lantern Corps. This would be like the jedis vs sith wars, being Sinestro the obvious Darth Vader of this franchise.
-End the story with something great, the Green Lantern Corps (not just Hal, hence the name even if Hal is the main character) win an spectacular battle in space, and Hal obviously defeats Sinestro in a cool fight in Oa before the guardians are murdered, avoid finishing the menace throwing the villain/s to the sun, that was lame.
