Although volunteer members of a re–enactment society, you need to have a keen interest to enable you to think and act like soldiers. Nobody will be forced to do anything they don’t want to do, but members should try to act "in character" otherwise the illusion of the reality is diluted.
Attention to detail and a feel for the period are also important. This creates realism, which is especially relevant when displaying this hobby to the public, as is a polite and helpful attitude. Enthusiasm above all else, is the one thing, which makes a real impression on people.