In the recently posted clip below, TDOVmusic, the crew that brought you "10 Essential Whammy Bar Techniques in One Song," presents "10 Essential Metal Rhythm Guitar Techniques in One Song."
These techniques show up pretty regularly in every sub-genre of metal. Of particular use, however, is the demonstrated difference between a gallop and a reverse-gallop rhythm. Take note!
By the way, the guitarist is playing the "very metal" Schecter KM-6, Keith Merrow's signature-model guitar.
Let us know what other essential rhythm techniques should be considered—and feel free to subscribe to TDOVmusic's YouTube channel.