Table manners are learned in childhood and judged unconsciously, which makes them the easiest place to accidentally signal disrespect. The universal safe behaviours: wait to be told where to sit, wait for the host or eldest to start, keep your phone away, try what you are served, and compliment the food. Get those right and most sins are forgiven.
The country-specific traps are the interesting part. Chopstick cultures have firm rules: never stick chopsticks upright in rice or pass food chopstick to chopstick, as both echo funeral rites. In much of South Asia, the Middle East, and Africa, eating with the right hand is proper and the left hand stays out of the food entirely. Slurping noodles is appreciative in Japan and rude in the West; finishing your plate signals satisfaction in some cultures and in others implies the host served too little. Blowing your nose at the table is offensive in much of Asia, while resting hands in your lap versus on the table flips politeness between France and elsewhere.
Habits from home worth suspending: rushing, salting food before tasting, and declining dishes outright. Observe your hosts, pace yourself to them, and copy shamelessly; it is the sincerest compliment.