Find an elevator and position yourself near the control buttons. When some people enter and you start moving hit the alarm buzzer and scream like you are falling. Then say you were just joking. That should start up a lively conversation.
Damn you. I work in a tower block with a really long and boring elevator ride. I just know that this idea is going to pop RIGHT back into my head next week and I'm going to have to fight not to do it! I bet at least one of them believes it and screams just because I am... No! Stop these thoughts!
Anyway, there are a number of threads on how to perform small talk tasks and carry out mind numbingly boring conversations with NTs. Like, start with an open question (did you do anything this weekend?) and if they answer, drill slowly into specifics without getting too personal too soon. I still keep notes on people, like what their hobbies are.
However, it doesn't sound like this is your problem, it sounds more like your problem is in your head. You might be going through the oscillation phase that we all experience, where you either try too hard or don't try hard enough.
If we try too hard, we scare people off with our intensity and we over analyse our conversational performance. Measuring our performance with metrics, such as 'does the person initiate a repeat conversation with me or avoid me?'. If we don't try hard enough we end up grunting or avoiding people.
The plus side of the "over trying" phase is that we can apply ourselves to research, improve our skills and then practice on the next poor neurotypical that stumbles into our paths. So if you are in the "over trying" phase, then that might be a good thing, it might take to to the next level of conversational techniques. Maybe you could hand out questionnaires after each conversation? "how did you rate my conversation skills today?", "was I a) congenial b) boring or c) creepy." "and how are you reacting to this questionairre?"...
