Your effort points are the white diamonds on the bottom left of your screen. You use these points when you pick special answers during conversations, making special observations while looking at things or for special skills like "reach" and "unlock". Simple enough, use all of your points and do not refresh them (with honey or royal jelly) until after the achievment has popped.
Easy to pop while doing the medusa puzzle or in the secret room after the medusa puzzle (lots of opportunity to pick special answers)
Can be popped naturally but easy enough to pop early in the game.