5S
Most companies start their Lean journey by performing '5S' beautification activities because an important customer is going to visit. Starting their Lean journey this way is followed by failure because they cannot maintain the process and the reason is simple, 5S is not a tool, it is a philosophy that is based on understanding when something is not as expected. For example, can you walk up to a machine and within 10 seconds learn how well your machine is performing? If not, you probably have implemented 5S as a 'tool' instead of a 'way'.
5S Information
Gemba
The danger of Gemba is believing that the goal is catching people doing a bad job. This tool is not about people, it is about the process and if there are people involved in the process - can they follow the process. If they are not following the process then something is wrong with the process, which leads to Kaizen
5 Why
Is an iterative process that utilizes the PDCA cycle and/or KATA to learn about a problem and then solve the problem.