Cut the potatoes into 1/4 inch by 1/4 inch (or smaller) sticks. If they are bigger they don't cook very well.
In a large bowl rinse potatoes once with cold water.Then fill the bowl with cold water and add a bit of salt let them soak for at least 30 minutes.
While the potatoes are soaking, pour 3+ inches of oil into the Dutch oven and heat it to 350 degrees f. The more oil you use the more potatoes you will be able to fry at once.
Drain and dry the potatoes thoroughly. Take a smallish batch of the fries and put them into the oil. Watch the temperature carefully if it drops below 300 degrees f you need more oil or to fry fewer fries at a time. Remove the fries and place them on a wire rack when they just start turning golden. Temperature is very important if it drops too much the fries absorb oil and become greasy.
After frying all the fries once increase the temperature to 375 degrees f. Fry the fries again removing them when they become golden brown. If they are still very hot from the first fry you can fry more at a time during this step.