One Day At A Time

so i’m really bad at making roast beef in the crockpot, and i’m doubly bad at making gravy of any kind- my kind hubby was so nice as to butter me up and say that our sunday dinner was great- i thought it was horrible. the meat was dry and my gravy had lumps. i consider myself a good cook- but where meat and gravy is concerned i’m about as smart as dirt. does anyone have any tips? I filled the crockpot up to the brim with water- does that make a difference as to how juicy the meat turns out? Any advice regarding meat and gravy would be greatly appreciated.