To learn Weezer - Only In Dreams chords, grasp the musical fabric of the song with this sequence - Bb, Ab, Db, Gb, Ab, Ebm, Ab, Db, B, Bb, Ab and Gb of chords. I suggest starting at a calm pace of 39 BPM, and as you gain confidence, approach the song's BPM of 78. For a balanced pitch, adjust the capo with respect to your voice and the song's key: Gb Major.