The secret to being a good conversationalist is to have the other person do most of the talking, and everyone's favorite thing to talk about is themselves.
Being, and therefore appearing, genuinely interested in what the other person is saying about themselves creates the best feelings in the world for the other person, and you won't run out of things to talk about.
"You just got a new dog? Cool!"
Then you can ask any follow up question you like.
What kind? What's their name? Where'd you get them from? Do you feed them "people food"?.. etc.
One question at a time of course, and avoid queuing them up in your head. When the other person is talking, try very hard not to think of the next thing you're going to say. If you do that, you'll miss what they're actually saying and eventually say something that makes it clear you weren't listening. Similarly, you'll miss out on each new bit of the conversation, and those new bits are the basis of new, honest, follow up questions.
You don't have to be interested in dogs generally, to be interested in them temporarily. "Being interested, intentionally" is a skill you can improve.
Don't try to direct the flow of the conversation too much either. Go into your next conversation with friends, family, coworkers, or strangers with a truly open mind about what you're going to talk about, with no agenda, and be happy knowing it could change at any time.
Your job is to listen and ask more.
A lot of supposed "conversations" are just two people looking at each other, waiting for their turn to talk. If you're going to do that you might as well each write your sentences down beforehand, exchange them, and then throw them away without reading them.
The truth is, nobody wants to hear what you have to say. They don't want to hear what I have to say. They want to tell you about what's going on in their lives and what's important to them.