DJ Tech Tools posts a great mini-tutorial with some tips on using Drum Racks and Clips for DJing. Ultimately, DJTT recommends a combination of Racks, Clips (using different launch modes), slicing, and Simpler/Sampler's controls to make the DJ template that's right for you. Full article at DJ Tech Tools
Scratch sounds without a turntable? It's easier than you might think, using the envelopes, filters, and sample start controls in Simpler. DJ Tech Tools' Mad Zach lays it down in this video:
Grab the template as a free download from DJ Tech Tools.