To make beef gravy taste better, you can add flavoring agents such as Worcestershire sauce, red wine, garlic, onion powder, or herbs such as thyme, rosemary, or sage. You can also stir in a small amount of butter or heavy cream for richness and smoothness. Additionally, adding a splash of acid from lemon juice or balsamic vinegar can help balance the flavors of the gravy. Adjust the seasoning to your taste, and gradually add these flavor boosters until you achieve the desired taste and consistency.