To begin with, the first thing every company should do is create an anti-harassment policy and let their employees know that they are protected. In case sexual harassment occurs, the employee should be afraid to tell about that. After that the person who has done it should be punished. All employees need to know that sexual harassment will not be not tolerated in the workplace.
When complaints about sexual harassment appear, it is of vital importance to deal with them in detail. Every case should be investigated. Otherwise, you will not prove to your employees that you are very serious about it.
One should not also forget about presenting relevant information about sexual harassment to your employees as well as educating them on the issue. Surely, it is also important to have staff who are experts in this field in order to observe the situation in the workplace, prevent as well as respond to sexual harassment in case it occurs. Preventing sexual harassment is that kind of issue which should be tackled as soon as possible.