Use a large pot of water
Add plenty of salt to the water
Bring the water to a full boil
Add the spaghetti and stir immediately
Cook until al dente
Reserve some pasta water before draining
Drain the spaghetti without rinsing
Heat your sauce separately
Combine spaghetti with the sauce
Add reserved pasta water as needed
Toss well to coat evenly
Finish with olive oil, butter, or cheese
Serve immediately