Here's how I do it:
First, I preheat the oven to 400 F.
Next, I peel the sweet potatoes and cut them in half vertically. I cut each half lengthwise, and then cut each of those halves lengthwise as well. Then, I cut them vertically into half moon shapes.
I line a baking sheet with foil and spray it with non-stick olive oil or coconut oil spray. I spread the sweet potato pieces out evenly and spray them with the same olive oil or coconut oil spray.
You can add any seasonings and spices that you like, but I like to keep them plain! You can make them sweet by adding cinnamon and then tossing them in sugar-free or regular maple syrup, or make them savory by adding spices like garlic powder, chili powder, onion powder, salt, pepper, etc.
Finally, I bake them in the oven for about 25-30 minutes, or until soft and just about golden brown.