No real good way. Replace the thermal compound with a high end one. Thermal pads, same.
Cooling pads help mostly by getting a laptop off of surfaces, though the added airflow doesn't hurt.
Theoretically, 90C is about right for the CPU with a true max of 100 or 105 before shutdown. Nvidia GPUs will throttle at 83C typically. You can force the GPU to run hotter, but that can actually make performance worse. You really aren't in control there, only the boost algorithm really decides clock speed.
Voltage is the real killer of components, heat less so. But the cooler the better, more efficient.