Salt your pasta water, never add oil, and don’t rinse.

Salt the water.

Mario Batali says you should salt your pasta water until it “tastes like the sea”…

Don’t add oil.

NEVER add oil to your pasta water. … Because when you add oil to your pasta you make it slick and the sauce won’t stick well to the pasta.

Don’t rinse.

The starchy water that the pasta boils in has all the goodness in it and helps the sauce adhere to the pasta. Rinsing also makes your pasta get cold quickly. 

https://www.thekitchensnob.com/cooking-tips/