So it's weird. I feel totally comfortable in commercial auditions now because it's usually back to the same casting agencies seeing the same people I've been auditioning for and with for several years now. Film and theater is different -- less familiar, often more formal (at least in the sense that you're dealing with strangers).
Anyway, today I felt totally prepared. Got my sides down, read the script twice, did some research, thought about the character, etc. And yet still it was awkward. People across a table, fellow readers in chairs across the room, a hemmed in area to stay in for the camera. The biggest deal, though, is having no knowledge like I have in commercial auditions of how much I can/should engage in conversation, ask questions, get familiar, etc.
Mostly I just follow their lead, speak when spoken to, etc., which is the safe way to go. I got to do several reads with different direction, which is great, but at one point my heart started pounding right through my ribs, which was really weird. I hope I was able to "use" that in service to the character. And that nobody could hear it -- to me it sounded like thunder.
Overall acquitted myself well. It's a character I'm pretty familiar with -- kinda nerdy. But he's supposed to play piano and sing harmony, so if that's important to them, I'll doubt I'll be going back.