To learn Aaaa - Blue Comet chords, these are the chords to practise in sequence: Dm, F, Gm, F, Cm, Bb, C, Db, F and Dm. A strategic approach would be to train at 45 BPM initially, and then accelerate to the song's tempo of 90. Considering the song's key of Bb Major, position your capo to suit your vocal and chord preferences.