Resistors are your friend! Using a simple resistor can greatly change your circuit and influence the end tone. In guitar wiring, resistors are used in a few applications to achieve different things. The below videos cover partial coil splitting and using resistors to trick pickups into seeing a different pot value.
Partial coil splitting uses a resistor to partially shunt the coil to ground, rather than the full coil as in with a typical coil split.
As well as coil splitting, resistors can also be used to change the resistance value of a pot for any given pickup. Some circuits combine both humbuckers and single coils but it can be tricky to decide whether to use 500k pots or250k pots. The below video demonstrates how to use resistors to balance typical Telecaster and Stratocaster circuits that use both humbuckers and single coils.