Google suggestions help data come from user searches history.

I do not know what are the filter that Google apply to determining if the queries come from real users or not. Some elements can be these:

• user agent
• IP address
• delay from queries
• click on result links
• accept cookies

Short answer: you can't.

The algorithm behind the Google search suggestions rewards "emerging searches" that those searches that have seen a particular growth in a short period. Therefore the algorithm relies heavily on user behavior. To change the suggested keywords you should take action to modify the behavior of many users such as an offline or online event that creates large amounts of research. In any case the result is far from guaranteed.