Subclips are smaller parts of the bigger project. Use the Make Subclip command early and save yourself some time when you get to the timeline.
The new sync lock feature in Premiere Pro CS4 is a very useful tool that will maintain the relationship between clips in multiple tracks so that when you are editing you make changes to one clip, Premiere will keep your edits in place
Franklin McMahon talks about batch coding in Premiere Pro CS4 and getting the software to render video projects out to different file formats for different platforms.
Premiere Pro CS4 has made it easier to apply multiple effects to multiple clips, either by cutting and pasting attributes from one clip to another, or by creating an effects preset that can be applied to any clip with one step.
Rich Harrington talks about one his favorite new features in Premiere Pro CS4; the audio transcription options.