I find adopting a IDGAF attitude along with some rationalizing helps. I haven't seen this person before, I likely won't see them again so what does it matter? I mean even if I will see this person again, as long as I don't have to work with this person, then I don't care if they like me. Yes I will stutter, stumble over my words and may make a fool of myself but oh well, IDGAF. It helps insulate me from the vulnerability of anxiety.
For people that I need to like me, well simply doing exposure therapy will decrease the anxiety over time, but I don't really encounter that scenario all that often because I already have friends who accept me.
"It's better to be prepared for an opportunity and not have one than to have an opportunity and not be prepared." -- Whitney Young Jr.