Zhuang Fangyi Rotation at a Glance

Zhuang Fangyi has two damage cycles: one in normal mode and one in ultimate mode.
Zhuang Fangyi Damage Cycle (Cycle 1)
Before starting, you need an Electric Infliction teammate like Perlica. Zhuang Fangyi unfortunately cannot inflict Electric on her own in normal mode, so Cycle 1 breaks without party help.
Start by lightly applying Electric Infliction with Perlica. Then land Zhuang Fangyi basic attack finisher on an inflicted enemy to trigger her Combo Skill.
Press Combo Skill to convert Electric Infliction into Shock. If this is difficult, review the red highlighted parts in Zhuang Fangyi Party, Usage, Gear Setup, Skill Priority.
Now consume Shock with Zhuang Fangyi Battle Skill (BS) and raise Thunderblade stacks to 6 or higher. (Ultimate Battle Skill grants 3 free stacks, so 6 is enough.)
Early on, one Cycle 1 may not reach 6 Thunderblade stacks, so repeat Cycle 1 until ultimate gauge is full. Enter ultimate even if 6 stacks are not ready.
The first Battle Skill after entering ultimate costs no SP and grants +3 Thunderblade stacks, completing 9 stacks from the earlier 6.
You are now ready for the main burst cycle: Cycle 2.
Zhuang Fangyi Damage Cycle (Cycle 2)
In ultimate mode, Zhuang Fangyi can inflict Electric on her own without teammates like Perlica. Battle Skill applies Electric Infliction.
Start with Battle Skill for Electric Infliction. Then, like Cycle 1, land the basic attack finisher, trigger Combo Skill, and convert to Shock.
Next, consume Shock with Battle Skill. Unlike normal mode, ultimate Battle Skill also reapplies Electric Infliction, creating Cycle 2 where infliction, Shock, and consumption repeat very quickly.
With 9 Thunderblade stacks already prepared and faster animations in ultimate mode, Cycle 2 DPS becomes extremely high.
When ultimate ends, return to Cycle 1.
Expanding to Party Cycle
An Electric Infliction operator like Perlica is locked in, so pick the other two members. Usually one Vanguard for SP recovery and one Supporter for healing is stable.
Adding them may slightly modify the base cycle, but the overall shape stays similar, so play according to your preference.