At high frequencies, additional charge accumulation causes an increase in capacitance at the corners of the trace bend and, therefore, a concentration of electric fields. Minimize the length of traces by using care in placing components. Avoid long runs, because they generate and pick up radiated noise from around the board. Such long runs are a common source of crosstalk. Avoid long parallel traces, unless they are differential, because they induce crosstalk.
Differential lines provide a canceling effect on noise due to their complementary nature.
If you must run single-ended signals, keep them as short as possible and remember that the amplitude of crosstalk between two traces is directly proportional to the length the two traces run parallel and inversely proportional to the spacing between the traces. Avoid running digital traces over analog power planes, because these traces may couple noise into the planes, which then pass noise to sensitive analog devices. Terminate transmission lines as close to the device pins as possible to avoid transmission-line reflections. Decouple every high-speed device. Large IC packages with many power pins need more decoupling and may require several capacitors.