It's hard to make a good impression when you're worried about making a good impression. You're concerned that you rub people the wrong way. Well, we all do that sometimes, and you need to remember that you won't please everybody. Actually, you may only make an impression on a few, but that's normal as well.
Think about this: focus on the people around you without wondering what they think of you and without feeling you have to be important. I've had to work hard on my timidity (I don't know if this is your situation - it may not be), and I had to realize that what other people were thinking of ME and how much they paid attention to ME were just not that important - that I wasn't the center of the universe.
When I understood that, I felt freer to smile at people, to say hello, to be interested in THEM (even when the talk flows around me but not to me), to want them to have a good time. It helps me to look at them, to listen to them, to ask them questions about their favorite subject - themselves - to let them lead in the conversation (responding with more questions when possible), and to bite my tongue a lot.
Small talk is supposed to be pleasant talk conducted in a pleasant way, so an abrasive person or an abrasive subject can sometimes be handled gracefully by asking more questions (even questions leading away from that abrasive subject).
When you show interest in the other person without trying to get him/her interested in you, other people will often start to think you're very likable. You probably realize that others' doing this has the same effect on you!
Hope this helps a bit.