Knowing a few rules of the Chinese table will instantly make you seem clued-in and welcome.
Chopstick rules: never stand chopsticks upright in rice (it resembles funeral incense — a taboo); don't point with them; use serving chopsticks for shared dishes (increasingly common); don't rummage through a plate.
Seating and starting: the seat of honor faces the door with a wall behind it, for elders or the host. Wait for elders or the host to pick up chopsticks first, and rotate new dishes to the elders.
Lazy Susan: rotate clockwise, never while someone is reaching, and stop it gently after you take food.
Toasting: when toasting an elder, keep your glass rim lower than theirs. "Ganbei" means finish the glass; "suiyi" (as you wish) allows a sip. If you don't drink, toasting with tea is perfectly polite.
