。
That was a shrewd approach.
Literal
That [topic-は] shrewd way was.
抜け目のない 'shrewd, sharp, on the ball' literally means 'without a missed eye' — drawn from the image of someone who never has a 'blank spot' in their attention. Combined with やり方 'way (of doing things) / approach,' the phrase praises (or warns about) a strategy that overlooks no angle. Short and evaluative.