Professional deck ovens inject steam for the first minutes of baking, and you can approximate this at home. Steam keeps the outer crust gel soft and stretchable so the loaf can expand, then evaporates and lets the crust brown and crisp.
The Dutch oven is the easiest method: a preheated cast-iron pot traps the loaf's own steam perfectly for 20 minutes, after which you remove the lid for browning. Without a pot, put a preheated metal pan on the oven floor and pour a cup of hot water into it right after loading, then shut the door fast.
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Stop the steam after the first third of the bake; extended steam makes a thick, leathery crust. A sprayer of water is the least effective option and can crack oven glass, so prefer the pan or the pot.