Add "Es","As","O","A" to the end. If its Ella (feminine) and the "as" "a", male (El & ello) add the "O" and "Es" it really matters what to object is by nature. If its Yo, add O, but if the object is (feminine) or (male), and you are a girl for example its "Mi amiga" but if your a boy, "Mi amigo" this is basic stuff that you can use on objects, When I speak spanish thats what I do.
