What kind of punishment and when?

Some mild punishment (that does not involve any harm done to the dog mentally or physically) is in some cases recommended. It is very important to choose the right timing. This means that you can raise the tone of your voice say NO and maybe also move your finger in a strict way, or take away her favorite toy when you catch her doing something wrong.
The same actions would not be effective if they take effect after the wrong has been done without you being present and the punishment takes place on the wrong timing.