Sketching

Sketching for interaction design

• The Messy Art of UX Sketching
• Storyboarding

General sketching techniques

• Draw a Box - Series of tutorials on sketching
• Martijn van de Wiel's Design Sketching video tutorials
• Terry Gilliam on cut-out animation

Read more

• Sketching User Experience by Bill Buxton. Makes the case for sketching and illustrates how it works in practice. See also the associated Workbook.
• Rapid Viz, Third Edition by Kurt Hanks and Larry Belliston (2006) introduces sketching techniques for objects, environments and people