Put the baking sheet into the oven and set the timer for approximately 30 minutes. However, after 15 minutes, take the baking sheet out to stir and flip the french fries. This will make sure the french fries are cooking evenly on all sides, and will avoid burning. Once you stir them up, add the french fries back to the oven to bake for the final 15 minutes. Make sure you are watching the fries throughout the baking process.