The secret to cooking pasta properly is to use plenty of water. Choose a large pot that holds at least 5 quarts. Be sure the water is at a full rolling boil before the pasta is added. When the pasta goes in, the water will stop boiling momentarily. Immediately stir it around to keep it from sinking and sticking. Oil added to the water will only rise to the top and does nothing to prevent pasta from sticking, but tossing the finished pasta with a little oil after draining will help keep it loose.
Al dente is an Italian term that means “to the tooth” and refers to the degree to which certain foods, usually pasta and vegetables, are cooked. These foods are cooked until done, but still have slight texture when bitten. They are not raw, or crunchy, nor are they soft.