Make friends and conversation with people that you otherwise wouldn't.

The more people you interact with, the more likely you are to get different perspectives, however this is most effective if you seek out those that are outside of your bubble.

If you do it on a social media site that tracks your choices, it will change what it serves you, however you're still being limited by what their algorithms choose to serve you. Ultimately, because of the way that these algorithms are designed, it's very difficult to expand your mind and see different perspectives if you use them.

Better is to do it in a place where the people with different viewpoints congregate - either in real life or online. Maybe go to a large public gathering for something, like a concert or a meet up, but try to find groups that are outside of your usual comfort zone.

I find that IRC is a great online analogue for that. You can go into different channels and talk to people with different views. The drawback is that people using IRC are generally all the type of people that know something about computers, so it's not a truly diverse sample set.

Beyond that, when you're out in public start talking to random strangers. Make conversation and make new and different friends. You'd be surprised at how open to conversation some people are. But even this isn't perfect as you'll only be exposed to the extroverted people that won't shy away from talking to a stranger.

It's hard in today's day of social media and content served by algorithms, but it's possible. You just have to put the legwork into creating and maintaining the types of relationships that people used to have pre-technological revolution. It's hard, but if you truly want to expand the range and diversity of people you know and talk to, it's currently the only surefire way.