Tuning is one of the most challenging stages of a build. To make things easier, you can simply use a tuning profile that we know works:

These tune settings are for specific builds with specific parts and firmware as listed. You should use the exact parts specified. If any of them are different, it can potentially not work or require a different tune.
Motors
In general, changing the motor type is ok provided it is the same pole count, size and kv.
ESC
Changing the esc or esc settings can affect the tune. It is recommended you use the same as specified.
Firmware
Every detail matters. The firmware versions, for both BetaFlight and BlHeli and the settings applied can all affect the tune. Use exactly what is specified for those parts.
Props and batteries

These are the two most critical factors in terms of tune compatibility. Changing to a different battery or propeller will change the tuning requirements. Use the exact propeller and battery types specified.

XNOVA Lightning 4S, 5045 Cyclone

Powertrain developer / tuner: Yiming Teng

EFAW 2407 4S, 5045 Cyclone

Powertrain developer / tuner: Adam Clarke