@SarahGen-- The powdered eyebrow products that look like eye shadow work better than eyebrow pencils in my view. They are applied with a brush and look more natural.
I suggest that you try one of these eyebrow kits in taupe for coloring in your eyebrows. To make it look natural, apply only to the areas where your brows are sparse and then brush through to spread the product.
If you don't want to invest in one of these, you can also use regular eye shadow and an small eye shadow brush. It works the same. Just make sure to blend it nicely and brush through at the end.