Stew, any tips to making the gravy in it really tasty?

Make a roux (paste of fat and a binder, like flour) first. This is where you melt fat (er is good) in a pan and add in an equivalent amount of flour to form a paste. If you let it cook down a bit, it starts to toast the flour a bit, turning it brown like peanut er and adding a roasted, nutty flavor to it. You then add water to a pan of hot drippings to deglaze it (like after you brown the stew meat) and add the roux. Stir this over low heat until it simmers and thickens.