To play any kind of modern music you need to know all the upper extensions for chords in every key. The starting point for this is the scale tone 7ths, shown here in the key of D major. Learn these chords in root position, then in inversions and then as arpeggios. Use them to play through various chord progressions in the key you are working on, e.g., II V I , I VI II V and I IV VII III VI II V .