Believe it or not, just a minute of less cooking time could make all the difference. Let the pasta be slightly under-done so that it cooks well while mixing with the sauces.
While the pasta is boiling, keep stirring it every now and then to prevent the pasta from sticking together.
Adding oil to your pasta water could be counterproductive and would in fact make the sauces slip from your pasta since it would become too oily.
Make sure to add adequate salt to your pasta water to properly season the pasta. It is also said that salt may make the water boil faster.
Rinsing the pasta in water after boiling is a big no. The natural starches and salts should be retained and not rinsed away.
It is important to drain the excess pasta water after the pasta has been properly cooked to retain the texture of the pasta.
Never throw away the water that you boiled pasta in to use it to thicken your sauces and make sure they mix well with the pasta.