Making gravy takes a little practice. Seldom can you simply combine the ingredients exactly as called for in the recipe and have the gravy come out just as you want it.
You must have the skill to observe the appearance of the gravy and know if the thickness is correct. And, you should always taste as you go to determine if the seasoning is the way you want it.
But this is not difficult. It is only a matter of remembering how the gravy came out the last time you made it and adjusting ingredients and/or cooking time to correct anything you did not like.
This white gravy goes well with chicken, turkey, rice or potatoes. And, remember, always serve your gravy steaming hot.