Find your key in three minutes
1) Play the song you want to practise. 2) Sing along to the first line of the chorus in the original key. 3) If your throat tightens on the high note, drop one semitone at a time. 4) If it feels easy but the low notes disappear, raise one semitone back. 5) The point where the top note is slightly challenging but never painful is your key.
In most pop songs, men find their key around -5 to -3 semitones and women around +2 to +5 semitones from the original.