So currently I'm trying to learn how to play knives and pens by bvb and also unholy confessions by a7x. I kind of got knives and pens down but I'm wondering if there is any tips for having to mute basically every other note in the riff/lick (not sure which one is which). Also when i hammer on and pull off the 8th fret and slide to the 5 and then pick 12 10 8 7 (i think those are the right notes) It tends to just blend together and not sound as nice as the song. If you heard the opening riff/lick to the song I think it would help you answer this question.

P.s. Sorry for putting this here but nobody answered it in the technique section and I know lots of people are here.
Never heard those songs but on palm muting, try holding you palm on the muting position and then rolling or sliding your palm back behind the bridge to unmute. You know that way you dont have to take your palm off the strings.