Bake for 20-24 minutes until fries are soft, then switch the oven over to broil (high) and cook an additional 1-2 minutes to get them crispier. My grandma always told me to broil with the oven door slightly ajar so thats how I always do it. This makes it easier to watch the oven contents closely since its only a matter of seconds before they'll burn.
Once they get a little brown and crispy, take them out, toss in some salt and enjoy!