Part 1 looks at "matchmoving our shot and using the data to create a 3D camera inside of After Effects, as well as starting to create the particle animation. Along the way, we’ll also go through a few quick tips on how to speed up workflow by using expressions to automate animation."
Part 2 explores "how lights work alongside Trapcode Particular to give us more control of the direction of the particles’ motion. We will finish off the animation of our particle effects, and create the beams of magic squirting out the end of the wands."
[update: Part 3 takes "a look at making the effects fit into the shot. We will make our particles glow and give them a bit of color, as well as adjusting brightness, matching grain and adding heat distortion. There are a lot of possibilities for extending the effects in this shot, I encourage you to explore these ideas further and leave a link in the comments section below."]
In addition to the “Priori Incantatem” effect, AETuts previously posted Create Harry Potter Titles by Robert Holtby and Creative Cow posted an After Effects tutorial by Michael Park on how to Create the Harry Potter lumos effect.
Beyond these, Andrew Kramer has several AE tutorials involving energy effects (for example 3D Light Casting), and Mark Christiansen's sample chapter Pyrotechnics: Creating Fire, Explosions, and Energy Phenomena in After Effects from his book After Effects Studio Techniques might be handy for further explorations.