Obviously we look for information about things we are interested in. We also pursue information that we think is valid or worthwhile, but the issue with both of those is that we miss out on a ton of information about perspectives different from our own. What measures do you or can you take to minimize the effect of this?
Find a closely held belief that you have. Say you believe (correctly) that Team Fortress 2 is the best online multiplayer game ever made. Now, open an incognito browser and search for, in my case, "Team Fortress 2 sucks." I look for someone who can convey thoughts in a clever way, who is entertaining and makes me go "OK you have a point there." Do this for everything that you like. It won't change your mind (in most cases) but it will let you know what the "opposition" so to speak is saying. And if you are going to argue about something, you need to know what the opposition is saying. This is how I came across William Saffire and William H Buckley. I disagree with about 90% of the things they say, but by reading them, I was able to defend my own beliefs better.
If you have the patience, read whole nonfiction books. It helps to have the entire story. Research them before you start. Read two books on the same subject from different views. There is always the audiobook bay. One thing I miss out on, because I'm in school, gen eds are way too basic.
If you're really interested in a controversial subject (Israel/Palestine, gay marriage, gun control etc.) it will take more than a couple books to really understand the issue. There are more than just two sides to any complex issue, but the most vocal participants in the conversation won't tell you that.
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.
Hubski-specific : Browse "global"
In "chatter" (if you use it), click the "global chatter - time" link, to see chatter from everyone, not just users you follow.
This may be too obvious, but you can use a search engine which doesn't personalize search results. Google knows a lot about us and it uses that information (including, say, social media) to balance results around what it thinks you'll like and what advertisers would like you to see. Using startpage, ixquick or duckduckgo can go a long way towards obtaining more neutral results. Startpage actually uses the google algorithms, minus personalization.
SOCRATES: What do you think? From the beginning people like this have never managed, whether on their own or with the help by others, to see anything besides the shadows that are [continually] projected on the wall opposite them by the glow of the fire.
GLAUCON: How could it be otherwise, since they are forced to keep their heads immobile for their entire lives?
SOCRATES: And what do they see of the things that are being carried along [behind them]? Do they not see simply these [namely the shadows]?
GLAUCON: Certainly.
SOCRATES: Now if they were able to say something about what they saw and to talk it over, do you not think that they would regard that which they saw on the wall as beings?
GLAUCON: They would have to.
SOCRATES: And now what if this prison also had an echo reverberating off the wall in front of them [the one that they always and only look at]? Whenever one of the people walking behind those in chains (and carrying the things) would make a sound, do you think the prisoners would imagine that the speaker were anyone other than the shadow passing in front of them?
GLAUCON: Nothing else, by Zeus!
SOCRATES: All in all, I responded, those who were chained would consider nothing besides the shadows of the artifacts as the unhidden.
GLAUCON: That would absolutely have to be. https://web.stanford.edu/class/ihum40/cave.pdf What you're asking, as I'm hoping this bit demonstrates, is an old question. It's as fundamental as asking oneself: "How do I escape boredom?" The Allegory of the Cave may be a good place to start for you. I'm of the belief that new concepts have their root in philosophy. Perhaps that's my own information bubble informing my opinion, but let's not ignore the fundamental idea that I wish to convey: Read. Start collecting books and reading them. There is no better way. Doesn't matter what genre the book is, just focus on it and master it. Just don't be that guy that brags about having not read a book since they were in grade school while expecting yourself to learn. The best way out of your own information bubble is by tapping into others'.
Make friends based on proximity. For a long time I made only digital friends that I really had a lot in common with and connected with. Eventually, for myriad reasons, I went insane and needed change in my life. I started talking to the people around me that I never really thought to "get into it" with. I don't agree with most of them, they don't agree with most of me, but they're good people who make valid points and we're both richer because of it.
If I'm ever in a conflict with someone, I try to turn it into a positive; "what can I learn from this?" I pay attention to people's mannerisms, body language, behavior to see how they work best. I constantly remind myself that diversity is what makes this life thing so awesome. I respect neurodiversity, and I understand not all minds work the same. I will pick a topic I've never heard about and read about it, just to expand my mind. If I'm involved in an altercation on the street that makes me angry, I'll somehow find the humor in it. If I read about a hardship people face that doesn't personally affect me, I'll read books, research online, watch youtube videos, documentaries, to try to get a better understanding, at least from an outsider's perspective. I watch youtube videos often of different cities: not the commercial chamber of commerce ones, but videos where someone who lives there takes their camera out with them for the day. This helps me see what it's like in other countries, this helps expand my mind, see beyond the narrow tunnel of my own nation. I always check facts, I always play devil's advocate, I insist on sources, I do not accept blindly anything anyone tells me. I do research on cognitive fallacies and so forth, to see the ways in which information can be manipulated. I study writing, psychology, behavioral conditioning in order to see how people present their ideas, and how one can be misled. I use the playground of my mind to reposition, juxtapose concepts and ideas, because turned upside down or considered from a different perspective, you can gain enlightening insight. What's true for me may not be what's true for another person; sometimes "reality" is subjective, and I try to keep an awareness of that. Above all, one of my most favorite phrases (paraphrased) of all time, from Plato, or Socrates, can't remember which: True wisdom consists of knowing that you know nothing.
Hubski's a good start - I found that, unless you mute people who disagree, even subscribing to tags that you are interested in often yields viewpoints that don't match yours about issues or news or things. The next step is not ignoring anything, I'd say.
Personally, I seek out and follow people I disagree with. Unfortunately, they don't always appreciate being confronted with someone who disagrees with them, but usually as long as both parties are mature, honest and open, one side or both sides can grow and learn from the interaction. Obviously there is a limit to how useful opposing view points can be, and you still have to be discerning and patient, particularly to avoid people who antagonistic, hostile or otherwise dishonest.
To use Hubski as a metaphor for a moment, it's like the difference between following users and tags. You'd follow a tag because it's a topic you're interested in, but you follow a user because you like what they have to say. A tag will only give you stuff that you know you want, but a person might post something on a topic you didn't know about. Each of us has a particular sphere that we like to peruse, some of which intersects with yours. When you follow a tag, you're just filling out your own sphere. When you follow a user, you explore a lot more outside your own sphere. Then, of course, your own sphere gets bigger as you discover new things. Non-Hubski-specific answer: when you have something in common with someone and become friends or acquaintances with them, let them expose you to new things. If you like their choice in music, and share favorite genres, you might ask them what books they like to read. If you've never read those books, try them out on their recommendation and see if you can expand your horizons. (Re-reading your question, I think my comment answers it in a roundabout way... short answer is I allow others to push me in new directions by showing me things we don't have in common (or didn't think we had in common as I was unaware of the topic completely)).