If you haven't already discovered them, Suzanne McNeil has 5 videos on zentangle at Jerry's
Artama. Once you've opened one of these, there are links to the others over to the lower right, so you don't have to come back here.
The Newest Way to Meditate: Zentangle Basics
Drawing Zentangle on a Dark Background Using Gel Pens
How to Incorprate Watercolors with Zentangle Drawings
How to Use Markers and a Blending Pen with Zentangle
How to Zentangle Using Clayboard and Micron Pens