To be able to get free likes on social media, people have to like the content that you are posting. For the people to like the content that you are posting, they have to be able to relate with it in a way that picks their interest. Without this, you will not get any likes. This then means that it is important that you know your audience. You have to know what it is relates to them and what it is that picks their interest. The only way that you can know this is by listening to them and monitoring their social media activity.
Granted, it will not be possible for you to engage each and every person on social media individually for you to be able to get this information. The good news though is that there are tools that you can use. These tools can help you to monitor and listen to your audience which will in turn let you know what exactly it is that they want. You will then be able to post that relevant content that will get you those free likes. Such tools include Google Alerts, Icerocket, Social mention just to mention but a few.