When first meeting people [unless I have reason to be defensive] I put on normal. Change my speech patterns [more professorial to academics, more Regular Joe to nonacademics]. Try to approximate eye contact, shake hands, try to find a question to ask.
But I can go the opposite way and max out my oddness if I feel the need to hold people off - think the caterpillar with the scary eyes on its rump.
I don't know that it works - the people who are going to like me eventually do and the others move away.
I have rarely been told I "seem fine" - more often people give me hints on how to change. But once this guy totally horrified me, smiling, touching me, and announcing to a group that I was "basically a warm person". Well, depends on definitions, but I have some warmth - I just was not prepared to have everybody told about it.