UPDATE2: Since challenges only last for one month, please read and update the comments for easy and possible challenges for this achievement.
UPDATE: Since October 2012 has ended, the mentioned challenge is not available anymore. But I do think that Colour Charge is the best way to achieve this. You just have to wait for an easy one that has more than 149 tiles.
I recommend doing the colour charge daily challenges for this.
The one in October 21th, for instance, is easy, and has exactly 150 tiles.
The only problem I had was with the shades of green in the last one, so keep them last.
Good luck and keep retrying.
1) You can make mistake as long as you correct it quickly.
2) Not all challenges have 150 tiles, so it is not possible to win this in every challenge.