I got this game two years ago at Christmas, back then I played it through on every difficulty from easy to expert (my first ever guitar hero), and after finally completing career on expert, I had a high score of about 180k in this song. I thought I never gonna make it because I had to almost double my score for the achievement. Now I tried it years later and got 260k on first try. Next time 297k, then 312k, 317k and finally 337k.
As everyone else have said: just practice the charts, the double notes (can't remember what they are called), you know what I mean. RY and GY, GBY and so on. Use star power on those notes while keeping 8x multiplier. A good start for the song is about 16-18k after the first solo of the song. If you're struggling, remember that you're playing with thousands, not tens of thousands here, so if you miss an easy note where you know you could keep your 4x multiplier, just restart the song. That's what got me the achievement.
Good luck everyone!
In Microsoft We Trust:
Xbox One 500GB (Day One Edition <3) • Xbox 360 4GB + 320GB (NTSC) • Xbox 360 E 250GB (PAL)
Xbox 360 E 250GB (NTSC-J) • Nokia Lumia 1020 (WP8) • Windows 8.1 Pro