Avid Minesweeper fans will immediately recognize that pattern.
Your opportunity to do this achievement (and 1-2-1) will come when you click a tile in a large area of no mines, and opens a large swath of the board. When this occurs, look at the edges of the newly opened area and look for those four tiles in order and in a straight line, 1-2-2-1. In most (not all) cases, the mines are in the tiles directly adjacent to the "2" tiles, and the safe tiles are adjacent to the "1" tiles.
When you see that pattern, immediately flag the tiles in front of the "2" tiles, and normal click next to the "1" tiles. In most cases, this will be a safe move. If the pattern is in the middle, though, you may hit a bomb due to a quirk of the bomb layout. If it does, just try again. Once you've successfully done this 10 times, the achievement will unlock.
If you want to get this quickly, find a puzzle where the pattern exists. Do the method above to flag and click the proper tiles, then deliberately fail the game. When the option popup comes up, click "Play Same Puzzle." Since you know where the pattern is, you'll be able to click right to it and repeat. Do this 10 times, achievement unlocked.
EDIT: JonnyBlazin5 correctly points out that you don't have to flag the mines, just click/clear the tiles to either side of them. I find it a help when playing Minesweeper to flag the mines, but for this achievement it is not necessary to do so.
EDIT: Reabo made a great YouTube video illustrating this solution. Thanks!
EDIT: CanadaAckis points out that the achievement now requires 20 repetitions instead of 10. Thanks for the heads-up. And thanks MSFT for changing the rules on us... :(