1 touch is not about restricted touches.....its about thinking ahead of the ball. That is: Getting a picture of all the options before the ball comes so that better decisions can be made in regards to the pass you want, and what sort of footwork is needed to get to this pass.
Below is a selection of exercises - progressing in complexity that could be used to develop a better 1 touch mentality.....this is not about being better at playing first time (although it is) but about better awareness before the ball arrives.