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Your best bet is a steamer and some hand manipulation. A decent soak with a steamer makes the collar malleable and you can then shape it to your heart's desire. As it dries, it'll set in the position. Easiest way is to do so on a hanger. When we're not sold out, we sell these. They're great for travel but if the majority of your steaming will be at home, these guys from Morplan will do the trick.
How do you keep Oxford shirt collars keeping this nice shape at the front? It happens with new ones but after washing goes flatter.