wonging
When I started to backcount shoes, I also felt a bit self-conscious. One way to deal with the self-consciousness is to find a table with someone of your ethnic, age, or gender demographic. Stand near that person and pretend like you're friends without talking to him. The person probably won't notice or care since he's facing the other way, but to the pit personnel, it seems like you're just hanging out with your friend. Eventually, you'll stop feeling out of place, and it be easy to backcount in any situation.
If possible, stand so that you're facing the table next to the one you are counting. Try to look interested in what's going on in this table, and occasionally glance over to the other one.
Also, you can do the cell-phone trick, where you pretend like you're talking on your cell-phone as you count the cards on the table. Feel free to leave the table in a negative count under the pretense of having to make a phone call.