If you were to sing or play me a root note I can sing the 5th, 3rd, b6th, etc just like that, so I'm fine at sign-singing things and I'm pretty tonally aware. My problem is that I am completely unable to identify individual pitches. If you were to sing or play me a random note, I will have absolutely no clue as to what it is (but I can give you the 5th 6th 4th with ease).

I feel like, especially as a composer, I should at least practice improving my pitch, but I don't know how to. The only way for me to identify keys is to take a song which I know *extremely* well, use the first pitch that pops into my head and go up or down from there, which is still a pretty dubious method.

Is there anything I should do? Even if sitting in front of a piano and smashing Ab for 5 hours is the only answer.

My flute book says: listen to the A of the tuning fork each night before going to sleep, and it should take a couple of months to be able to recognize just the A.
I am serious, it's in Trevor Wye's practice books.
I haven't tried it and don't intend to.