Richard Walter has shared some excellent advice for screenwriters on The Wrap which essentially boils down to one point: Lie.
Brad Johnson of Script Mag has written a great article covering what he identifies as the four essential elements that you script will need to end successfully.
Dave Trottier of Script Magazine has written a clever article offering up the three best ways to fail as a writer.
Danny Manus of No BullScript Consulting has written a new list, 50 signs of an amateur screenwriter.
Several years ago Joss listed his top ten writing tips.
This new video from Jacob Krueger takes a look at effective ways to juxtapose two stories against each other within a script.
Here's a great article by Craig Kellerman about making your ideas actually get on to the page in a way that a reader can pick up on.