Start the match off with Shabby's R-Action, more often than not it will counterhit. From here, time a Knuckle Train so that it will activate a bit after the opponent wakes-up. Then do an IAD over them a bit before they get up, 95% of the time if timed right (and sorry, I can't really explain the timing of either, if you have a basic understanding of Shabby, you should get it quickly) the opponent will get hit by Knuckle for 1.9k free damage, but it doesn't end there~ combo off of the knuckle a bit before the enemy can tech [relatively soon on normal hit, quite a while on counter-hit] and go into autocombo for a total of 2.6k. Once Guilotine Axe hits, press 5C to prepare another Knuckle and with the same timing, IAD over the opponent and do the whole thing all over again. This cycle can literally go on with ease until the opponent dies.

Because you are doing nothing but dashing, aside from opponents who do wakeup supers the second they Awaken, most of the time the opponent will not do any SP Skills because you are not actually pressing any buttons when Knuckle hits, making this a fairly safe strat.

If you manage to get the enemy in the corner somehow (ideally this method keeps the opponent bouncing back and forth midscreen since you IAD onto the other side of them each time), you can do an even easier method. After autocombo and Knuckle setup, just start backing up, the AI will recover and start to run towards you almost always, running right into Knuckle and staring the cycle anew.

If by chance the AI does happen to block Knuckle... who cares, do you know how + that ish is on block? you get pressure for free either way~

If something goes wrong:
If you get hit by... just about anything while going for this, Burst, you aren't going to use Shabby's IK, so use that quickly before you die. After you burst, don't pressure the opponent, just do a Knuckle and back up, the opponent will likely run into it, then you may pressure.

If you're really getting thrashed and have Awakened, Shabby's Brutal Impact is still a best bud of yours, and can set up the Knuckle tactic if it hits. Distinguishing between using the A version and B version can be very important, and some matchups favor the instant one.

If things just aren't going your way and you're in a bind, just use your R-Action again while being pressured to set your Knuckle up again.

Specific character strats
Yosuke: He's very fast, and might be able to escape the Knuckle strat, if this happens, fight him normally.

Teddie: Once he Awakens, he's gonna go for Circus Bear prolly, so abandon your pressure for a bit until it's done. Remember that if you're not holding D, Asterios will get hurt Circus Bear.

Mitsuru: She may not give a fuck about your strat, and seems to be one of the few characters who were able to get through a few times, if she does, abort all offensive tactics until she leaves herself open for a punish, then autocombo it and start the strat again.

Aigis: If you get a life lead, and are far away from Aigis, she'll start shooting at you with everything she's got... press 5D and just hold Asterius right there, he'll take every shot she has until she gets close again.

Shabby/Labby: Strat works just fine against them, but for safety's sake, I recommend the grab strategy until they create a clear opportunity to go for the Knuckle setup. A nice note is that since the Knuckle strategy ideally keeps them midscreen, you never have to worry about Brutal Impact, as you can just jump over it (though remember that Shabby's A version is very quick, so you still need to be on point for your jump).

Liz: What a pushover she's become, she too is free as air to the Knuckle strat, and semi-frequently use Thanatos in it, allowing you to Persona Break her. Once she Awakens, I still recommend going for the "jump over her wakeup" strat instead, again for safety's sake. That is unless she's currently Persona Broken, in which case, keep the Knuckle's goin' until Thanatos is back in action. I managed to double perfect Liz without any trouble here.