Tiara's Singing lesson; get a 100 rating on 3 consecutive songs using Tiara. This achievement is misleading, as, from my experience, they don't need to be consecutive just as long as at least 3 of 6 songs in the Gig are 100 ratings, this will pop. This is not a problem and you will often get 6/6 songs at 100 rating. You needn't get all Greats to get this rating but just need to do pretty well and hit at least around 99% of the notes. There are many songs which have weird parts which you will get many misses, however this doesn't appear to affect the rating, as long as you clear the song.