Try asking some people that you know and trust IRL. Ask them if you have ever made them uncomfortable - and then ask them how they tend to respond. Or just ask them how they react when they're uncomfortable in a conversation. As Spockette said - try asking a T for some help with this.

As to myself and my own interpretations: When I'm not comfortable in a conversation for whatever reason, I tend to try to change the topic and/or dominate the conversation. It depends on what kind of uncomfortable I'm feeling I guess. I'll also trail off in my answers or give brief responses that don't encourage the other person to continue. I also might actually "answer" a text on my phone, but it might just be me sending one to someone else to vent. If I notice other people doing similar things, then I'll try to change the topic and find a topic that I think they would like more. Or I would excuse myself from the conversation if that was an appropriate action.

I tend to just think of how I react, and then watch for that a bit when I'm talking to someone.

If you aren't sure on things like that though, try to avoid hot-topics like politics, religion, sex/gender issues, your bodily functions, etc. They could make people uncomfortable if they don't know you or don't like the topic.