If you brown the flour well before adding the liquid when making gravy,
you will avoid pale or lumpy gravy.
You can also make dark gravy with unbrowned flour by making a dark roux.
A roux is a thickener made from equal amounts of fat and flour. Heat the fat, add the flour, and cook over medium heat, stirring constantly until the roux becomes a deep brown. When making gravy with the roux, it will not thicken as well, so you will need more of it.
If all the above tips fail in getting your gravy to brown to a rich
color or you just want a quick and easy solution, add 1/8 teaspoon instant coffee granules and stir to blend.
Thin gravy can be easily thickened by adding a mixture of either flour
and water or cornstarch and water, which has been mixed to a smooth paste. Add gradually, stirring constantly, while
bringing to a boil.