PLAN to improve your operations by finding what things are going wrong identify the problems and come up with ideas for solving these problems.
DO changes that will solve problem on a small or experimental scale first. This minimizes disruption while determining if the changes will work.
ACT to implement changes on a broader scale if the experiment is successful. This means making the changes a routine part of your activity. Also Act to involve other areas affected by the changes and whose cooperation is required to implement the changes on a larger scale, or those who may benefit from what you have learned.
CHECK to see if the small scale (experimental) changes are achieving the desired result. Continuously Check key activities (regardless of any experimentation going on) to ensure you know what the quality of the output is at all times.