This is a ridiculous questions and shows a clear misunderstanding of introverts
Are you under the impression that extroverts have more to talk about than introverts?
It's the opposite, introverts choose to be solo, we aren't outcasted.
Many also enjoy reading and learning new things, so we have way more subject matter to speak on then you talking about the last party you went to.
Introverts can carry a spontaneous conversation much longer and of better quality then extroverts imo
This is incorrect and just an attempt to try to sound smart.
Now, to answer op’s question. It helps to plan ahead as much as you can. Or to the extent that you are able to. Based on the question, I surmise you’re not so confident in being able to spark a random conversation and to keep it going for as long as is necessary without being awkward.
I get it.
First, try to think of all the possible unpleasant situations that may occur when you’re about to go into a social arena. Plan ahead of what you will say if they actually do happen. Decide if you’ll even need to give a response.
Second, remember to smile. And BE CALM.
If you really want to control the outcome, learn to be calm. I’m repeating this because a calm man with a calm tone sends chills down peoples spines, especially women. I know this because I actually tried it.
In that same vein, monitor how you pronounce your words. This can be hard. But the harder u find it to be, the shorter u need to make your responses. In other words, learn to say a lot with fewer words. Master the dictionary. And no I’m not saying use big words. This is where the English language has the most benefits. You can say a lot in many different ways.