People debate on whether perfect pitch can be learned.
It's a fact that there are a very rare number of people that from an early age can perfectly identify pitch without ever having learned it.
It is a natural ability.
So where does that leave the rest of us who aren't born with this talent? The good news is that you can practice developing perfect pitch getting closer and closer to having better or perfect pitch.
You have to start familiarizing yourself with music.
It helps if you are training your voice to become a singer or if you are currently playing an instrument because you will daily be around these notes and pitches.
Do yourself a favor and start learning music theory.
Learn what chords are made up of and learn scales.
This will help your mind start to almost memorize sounds.
A 1st, 3rd, and 5th for example that make up most basic chords will sound the same relative to each other regardless of what chord is actually being played.
Your mind can gradually start to hear this and understand the difference and start hearing when it's not a 1st, 3rd, and 5th in that chord.
This is what is known as relative pitch.
It's the first part of perfect pitch that you have to become skilled at before moving on.
Another exercise is picking a single note and trying to memorize that note and that note alone.
One common one that is picked to practice would be middle C.
Every time you pass your piano or the instrument of your choice, try to picture the sound of middle C in your mind or hum it then play it to see if they match.
Do this multiple times a day until you perfect just this one note.
From then on you will have a note in your mind that you can use your relative pitch techniques to know if it's a higher or lower tone making it easier to start identifying other pitches accurately.
This is how something like perfect pitch can become a trained skill.