Over the last few years, I've travelled across five continents, training many professional broadcast After Effects designers, and a constant among them is the wide use of Red Giant Trapcode Particular to create sparkles, fire, rain, snow and general visual flourishes.
Although I've been using Particular for many years, I'm still learning new techniques all the time, and this is particularly true of Harry Frank's new Particular training series.
As well as showing fast ways to produce classic mograph techniques (including things like text dissolving into particles), he dives into the technical side of particle systems, with extremely useful techniques for improving the speed of your renders in Particular. I can't recommend these tutorials more highly.
What's more, this training is free.