All this week, as Vulture has been covering the summer movie season, we've been focusing on the record-setting wave of sequels. Why is Hollywood more addicted than ever to them? What's the origin of the prequel trend? And what happens to a franchise when it's run into the ground? And now it's time for some creative advice: We decided to find out just what it takes to make a successful sequel, and we took the question to some people who would know: Oscar-winning screenwriter Christopher McQuarrie, who just scripted The Wolverine for Hugh Jackman; Richard Donner, who directed all the Lethal Weapon movies (and part of Superman II before he was replaced); Brett Ratner, who originated one big franchise (Rush Hour) and joined two others (with X-Men: The Last Stand and Red Dragon) that were already in progress; Al Ruddy, who produced the first two Godfathers; and writers Jonathan Aibel and Glenn Berger, who devised this summer's looming blockbuster Kung Fu Panda 2. They gave us ten tips for optimum sequel-making, so would-be franchise filmmakers, pay close attention.