DJ Hero

As with many of the skill-based Achievements, you're best off using one of the low-intensity mixes like Queen/Daft Punk on Hard difficulty. After hitting a streak of 50 (this includes button taps, scratches, effects knob uses and fader moves), the Achievement will immediately unlock.

I know this is an easy achievement, but I wanted to post what I believe to be the easiest and quickest way to obtain this without any hassle. Choose Quicklist > Standard Setlist and scroll down to the track "Boom/Tap" by Grandmaster Flash, press X, then A, choose character, venue and Hard difficulty. The first part of this mix consists of 51 simple button taps. No scratches, effects, faders or any other of the more advanced commands.