darken your skin ( if your white) and look really nervous and fidgety with some hand luggage,
i was in an airport recently and there was a little old indian guy in the line to check in just infront of me, the guy he was with explained to the staff that he had only flown once, was from some sort of religious commune in the middle of the indian mountains, wasn't used to large crowds of people and didn't speak english.
due to this he was obviuosly nervous and kept checking hisbag and was generally restless and probably petrified
the other passsengers in the lounge were staring at him, pointing and a number went and spoke to security about him so obvioulsy he was scaring them