As I wrote in two previous articles in this series a few months ago, some of what separates elite PvMers DPS, which usually operates consistently at higher levels, are very small changes that aren't significant on their own but in aggregate can make a significant difference in performance. Perhaps the most infamous example of this is 4TAA, which involves manipulating the tick system to weave in functionally lossless auto attacks inside a standard rotation through switching weapons. While this is the most significant individual boost in the game within this category of techniques, others can help too.
One interesting technique involves maintaining Aftershock stacks through weapon switches that don't have the Aftershock perk on them. For those who don't know, Aftershock is widely considered the best on-balance weapon perk in the game. It deals area of effect damage every 50,000 damage dealt, with an average of 40% weapon damage per rank. If you switch weapons prior to the Aftershock hit to a weapon without the perk, your counter resets to zero. For this reason, most people try to have at least Aftershock 1 on all main hand weapons, for example with Planted Feet on the same gizmo, so as to not lose stacks. Unfortunately, for some special attack weapons, most notably the Guthix Staff - often used both for the +2 affinity and for being a surprisingly high damage hit - it is not possible to add a perk to the weapon, therefore always causing the player to lose stacks. This is avoidable, however, by once again manipulating the tick system. If you use an ability (or auto) with a wand prior to using the Guthix Staff special attack and switch to your staff on the same tick you use the special attack your stacks will be maintained. You can even see in the animation that it appears you're doing the special attack with your staff.
Here you can see me losing my aftershock stacks when performing a Guthix Staff special attack:
Here you can see me doing the described technique to maintain the stacks:
While the overall damage gained just from this is minor, it does provide a lot of possibilities for maintaining aftershock stacks through other usages. For example, some players have opted to purchase a second set of Praesuls in order to increase damage with abilities such as flanking. For example, you could do the same trick to switch to a wand with Precise 4 and Equilibrium 2 (P4E2) when you flank then back to your wand with Aftershock 3 all on tick to get a P4E2 boost stacks on top of your flanking hit. I haven't tried this and am not sure how sustainable/viable this would be without macros. I personally don't use any macros because I have no idea how to program them and they're still against game rules, but a Guthix Staff macro that tick switches weapons for you is among the most commonly used. Additionally, if you try incorporating this you'll find that having your special attack and standard staff key bound will really help. I imagine having the Guthix Staff key bound as well would help too but I don't have any room left on my action bars.
Another tick related technique is something I talked about extensively in a previous article so I won't go into great detail, but a (somewhat) recent update allowed players to key bind different spell books for the spell book swap ability (accessible while on ancients or lunars) allowing you to case it without losing any game ticks or on global cooldown. This, combined with a spell such as disruption shield which operates off of global cooldown can be a huge boon for surviving big bursts of damage or singular high hitting type-less damage. Examples where this is popular would be to block blue bombs at vorago (it even blocks pushback on phase 5 or 10/11 in hard mode!), Telos's phase 4 anima bomb, combo attacks at Angel of Death when basing, and artifact bombs at the Ambassador. Additionally, heal other is once again a popular spell in the group PvM meta. There are a lot of times, particularly at Vorago, where players can heal other eachother without taking damage - when you're being intercepted by a player with barricade, during phase transitions, and even right before you know you're taking a huge amount of damage you're going to resonance (most famously the Kalphite King green attack). This really helps with food consumption, and the advent of lossless off-GCD swapping has made SBS an even more standard part of any PvM setup. This plus colored rune pouches changed flexibility at the highest levels of PvM dramatically, and I hope after all the controversy surrounding it people will realize it's overall a good thing.