To start learning Tom Petty - Yer So Bad chords, delve into these chords sequence to get the song's feel: G, D, C, G, C, D, Em and C. Start with a comfortable 45 BPM and as you become proficient, aim for the song's BPM of 90. Align the capo with your vocal depth and chord choice, bearing in mind the song's original key: G Major.