Whenever I play a riff on more than three strings, the notes on each string sustain too long. The notes I just played keep going and it eventually devolves into a cacophony as I play more notes on different strings. What do you recommend for muting the strings after their notes outstay their welcome? Should I use my right palm or my left fingers? Or some other technique I haven't even thought of?
Either works. Use your palm if you want a chunky, audible stop (like a slap almost but electric). If you just want the notes to stop like a more digital sound, then mute by gently lifting your fingers off the strings, but not all the way. If you wan to pick the muted strings when bringing the notes to an end, mute using your fretting hand and strum the muted strings. This will be the most audible. All 3 methods are useful, so it really just depends on the situation and sound you're trying to get. I use them all.
Quote by sadSTATUE
Uhmmm... Well, apparently I was mentioned in a thread called "Japan and Lesbians."

Quote by Unknown_Biskit
Try typing "potatoes" with your dick then submit it.

My cover of Manchester Orchestra's "I Can Feel Your Pain"
Last edited by gatechballer at Jan 2, 2010,
What the above user said. Try each one of those methods out.

What I have to suggest I'm sure you'll hate the thought of but pays off very well in the end. I do it with any new riff or lick I have trouble with even still with my muting having gotten much better over the last year. Muting is a very complicated skill to learn whenever it comes to not muting too much, not making noise with other strings when you mute or even muting to accent certain notes.[basically more than your mute the 6th string chugga stuff] What you NEED to do is with these riffs you're doing is SLOW THEM DOWN. Observe what is going on. What strings are making the most noise? What is my muting hand doing? Is my palm sliding across the strings? When you figure out the problems, fix them. Build your speed up and all that which you have heard thousands of times before I'm sure.

It's annoying, but it's worth it. Muting is just all practice.
I remember that video that Freepower posted just above when I had this same problem a while ago, really helped me out. Give it a look.
Can't stop the spirits when they need you This life is more than just a read thru
I don't anchor my wrist and move my hand for things like that for example RATM, Killing in the name, just stalk the strings you want to mute with your palm, and mute when needed.