Guitar Hero Live

From the main menu, select 'live' then click 'Quickplay' to see a list of all the songs that you have unlocked from the main career mode/festival sets. Each time you finish a song you will be awarded with a score based on how many notes you hit, the type of notes available (e.g. Power chords will score higher than single notes) and the difficulty you played on (higher difficulties have more notes available to be hit). You can also make use of the traditional guitar hero star power in Quickplay. Once it has been unlocked by hitting all of the star power notes in a row (those of a blue colour with a lightning bolt in the middle) you can press the hero power button on your controller or tilt the neck of your guitar to activate it. Once done, you will temporarily double your multiplier and earn more points so you should do this during moments in the song when many notes or chords are available.

Each time you hit a note the score will be automatically contributed towards the 20,000,000 total needed. This means that should you restart or quit a song before it's finished, your running total up to that point will still count. Therefore it's highly likely you will unlock this while attempting the 'Ooh You Fancy' trophy. If you don't rack up enough points before you unlock it then it should still have contributed quite significantly so keep playing songs in Quickplay to earn the final points needed to hit 20 million.