I've been doing directed ear training online for several years now - if you think you have perfect pitch, you can actually test it at tonedear.com (I don't). I've been working instead on the first lesson, interval training. It plays two tones next to each other and you're supposed to identify if they're a major third, perfect fifth, octave, etc. I've been doing it for over two years and I've definitely gotten better, although I'm still not even at 100% at interval recognition.