Congrats cberman! I've just played my first 2 USCF rated games (2nd one was this evening). I had similar questions, this is what I've seen and what the tournament director told me:
Shake your opponent's hand before and after the game
Keep an accurate and legible scoresheet
If you touch a piece you must move it
No talking or other disturbances while the game is going. Silence your phone. When you've finished your game, go to another room to discuss. If you disagree with something your opponent did, stop the clocks and get the tournament director
To offer a draw, make your move, offer the draw then press the clock. To claim a draw by repetition, announce to your opponent that you are claiming a draw by repetition, press the clock but do not make a move. If your opponent disputes this an arbiter will check both your scoresheets. Note that constantly offering a draw when your opponent refuses is very bad form and constitutes a disturbance.
Delay clocks keep a few minutes back til the end. E.g. the tournament games in which I've played are G/90 but the clock is set to 85 minutes, with 5 minutes delay. This means that when the clock hits zero it will magically bring you back those 5 mins. In our tournaments all the clocks are set up this way
And most importantly ... ENJOY ! I've lost my first 2 games so far but am really enjoying myself

Well, I will be attending my first ever OTB (USCF-rated) tournament on Oct 29. I'm excited.
But what do I need to know? What's the unspoken, unwritten etiquette of these things? How, exactly, does one offer a draw? What's this deal with delay clocks, and requesting a delay clock?
I've read the FIDE rules; the USCF rules are hard to find (which is to say, they must be purchased). I'm a bit in the dark here. I'm familiar with such things as the touch rule, but some of the finer points of clock-stopping, etc, I'm not so sure about.