Crosstalk

Switching of the signal in one net can interference neighboring net due to cross coupling capacitance. This affect is known as cross talk. Crosstalk can lead to crosstalk-induced delay changes or static noise.

Double spacing   =>  more spacing =>less capacitance =>less cross talk
Multiple vias       =>  less resistance =>less RC delay
Shielding             =>  constant cross coupling capacitance =>known value of crosstalk
Buffer insertion   =>  boost the victim strength.
Net ordering        =>  in same metal layer change the net path.
Layer assignment =>  Change the metal layer of two nets if possible. (One s/g in metal 3 and one signal in metal 4).