I've struggled with this a lot and oscillated.
At first I would monologue and it was all about my interests. Then I tried to ask about them, but that went horribly wrong! It was more like an interrogation. In chronological order. I would start by asking about their education, their first jobs, where they lived, their marital status, children, future plans. Once I was told that my casual conversation borderlined on a job interview...
So now I try to find balance by reading a script that combines the fundamentals of small talk in combination with interview techniques. I shall call it, medium talk. It goes something like this:
F: hey
Me: hey what’s up
F: nothing much how about you?
Me: oh doing well (this is usually a lie), finally, the sun is out (small talk opener, don't talk about yourself and don't take their question literally)
F: yes, makes a nice change (sometimes they give information here)
Me: did you do anything nice this weekend? (starting to get personal)
F: not much, took the dog for a walk
Me: oh lovely (trying to sound like I mean it), what breed do you have (trying not to call it an "it")
Then, when you extract a small piece of information, that evening, note it down in a spreadsheet along with their first name if you remember it. Don't put last names in it or that's like creepy stalker territory, just revision notes.
Don't let anyone see it!
Then, follow a similar pattern on the next conversation and learn a bit more, only give details if they SPECIFICALLY ask. For instance, if they ask how the diet is going, say "fine". Often NTs get scared and confused when offered the volume of information that aspies are comfortable with. For example, If I ask about someone's diet, I am interested in the exact calorie count per day, the specific achievements such as cholesterol improvements, their successes and failures. When NTs ask they want you to say "hard work but going well" and leave it at that.
But, you may wonder, will there ever be any substance to a conversation ever again? Well, probably not, but if you can make your peace with this then you'll start to make friends. And every now and again, say once per 5 years, one of them might surprise you by being interesting.