Yeah, but what if you just suck at talking to people?
Only way to get better is to practice, sadly.
Good early stages are to try thinking conversations through on your own in your head, trying to come up with a variety of different responses to different comments. Finding a variety of basic "safe" topics to talk about also helps, as does finding some good ways to get a conversation started in the very first place (which is generally the most awkward moment of most conversations, I find). Beyond that you pretty much just have to talk to people, and actually pay attention to not just the conversational content but the way that the conversation flows. Practice makes perfect and all that jazz; nobody ever sits down and plays a bach piano concerto perfectly without ever having played the piano before, and nobody is a perfect conversationalist at the beginning, you become one by working your way through the awkward beginnings (those first mary had a little lamb playings on the piano) until you progress beyond them.
A few other big tips:
1) Questions are always good things to use in awkward conversations (though not to the point where everything out of your mouth is a question). When you are listening to the answer to a question you aren't doing the talking, but you are still viewed as an active part of the conversation. Combine that with the fact that generally the topic that people are the most comfortable on is talking about themselves, and it's totally possible to go through a conversation where 70%+ of it just consists of you sitting there listening. And as long as you actually pay attention to what people are saying and react with head nods/etc., then you're still an active part of the conversation and viewed as contributing.
2) When you do say things, try to (if possible) make them things that the other person in the conversation can draw parallels to (though that you still know enough to talk about). This is a big part of the active listening mentioned before, if you listen to people and learn what they have experienced, then that lets you make comments that connect with them specifically. For example since I'm a college student griping about loans/etc. works great as a smoother in conversations if you can get on the topic, because
everybody has some sort of story about it and can connect to it personally.
3) While it might seem a little pointless, it's worth checking out at least some of the basics on things that "Everybody knows", because it guarantees you to have a few safe topics that you can turn to that are guaranteed to connect with those listening (sort of like the loans topic I just mentioned). Knowing at least the basics guarantees that you can work with the topic and fit it into the conversation and gives you a place to go if it gets mentioned, instead of running into one of those awkward silences that show up when somebody tries to change the topic to something that nobody else knows anything about.
Honestly the biggest thing I can stress about being a good conversationalist is knowing at least the bare minimum basics of a variety of different topics that other people might be interested in. Combined with a few good questions you if you can find at least one thing that the other person in the discussion is interested in then you've found yourself a topic to ask questions about their interests in, which will buy you more time to find another topic that they like and that you at least know the basics about. A large portion of more relaxed conversations literally just break down to one person explaining something or telling stories about something while the other person listening, then a switch up to whatever topic you at least both know a little bit about. The best conversations come when you are both passionate about something, of course, but it's totally possible (and fine) just to get along by knowing the bare basics of something that the other person is interested in, so try to pick up at least some generalities of as many different areas as you can.