Like Eli said, the same stuff as a private. A sergeant is still an enlisted man. Add the stripes to the trousers and the sleeves to indicate your rank.
That said, what makes a sergeant different from an enlisted man was his knowledge of drill, his esprit de corps and his authority. A sergeant makes men work and makes them do work they don't want to do, so he has to have authority in his demeanor. A sergeant's primary responsiblity is to make sure everyone under his direct command is healthy and ready to face the enemy at a moment's notice. An eye for detail, a clever mind and a get it done attitude are some of the best traits of a sergeant. He sets the example for the rest of the company, so his musket is always clean, his box is always full, his canteen and haversack are always full, his knapsack packed, his gear clean and his brass shines. He is the first man on line for formation and the last to leave.
And, he occassionally lets the officers think they are in command.
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