Use a large pot that holds at least 7 quarts. The lighter the pot, the better; the water will come to a boil faster than with a heavy stockpot and―also key―return to a boil quickly after you add the pasta.
Salt the water once it comes to a boil. (Add salt earlier and it could end up pitting an aluminum pot.) The seasoning will give the pasta an essential flavor boost. For every pound of pasta, figure on 2 tablespoons of salt and 6 quarts of water.
Stir the pasta right after you add it to the water and then occasionally throughout the cooking time to prevent clumping.
Test for doneness about 1 minute before the time given on the package instructions. Dried pasta should be cooked through but still firm to the bite. (If it sticks to the wall, it's already overdone, so skip your sister's noodle-tossing method.) Fresh pasta will rise to the surface when it's ready. It should be chewy and have a uniform color throughout.
Don't break pasta to fit it in the pot. Let the ends stick out until the submerged sections soften, about 1 minute. Then stir to bend the pasta and push it underwater.
Don't add oil to the pot in an attempt to keep the noodles from sticking together―stirring with a pasta fork is much more effective. Oil also prevents the sauce from coating the pasta and makes cleanup a greasy proposition.
Don't discard all the pasta cooking liquid. Reserve a cup before draining to add to sauces for seasoning and body.
Don't rinse cooked pasta. It eliminates the flavorful starch that helps the sauce adhere; rinsing also cools the pasta.
Put these new skills to the test with kid-friendly spaghetti recipes.