Learn English – What’s the best way to say “while *working on* Project X”

When you don't know how to use your firearm, you become a menace.

As used here, menace is a noun meaning:

A person or thing that is likely to cause harm; a threat or danger

It doesn't really work in the OP's sample sentence, but I would suggest well-groomed. If we tweak (quite radically, I'm afraid) the sample sentence we'd get

A well-groomed woman who epitomizes practical sense, and style.

Collins Dictionary

A well-groomed person is very neat and tidy, and looks as if they have taken care over their appearance.

Collins also provides soigné as one of its synonyms, a French loanword which originally meant “to take good care of” (soigner) nowadays its meaning is closer to that of being elegant, chic, and well-groomed. Merriam-Webster says of it

It can also be used to describe people, as in an article about fashion designer Donna Karan: "Though her name is really pronounced 'Karen,' people said it with a glamorous continental inflection; it suited their image of a fashion designer: aloof, soigné, different from you and me." (Josh Patner, The New York Times, April 11, 2004)

• ‘As he stops to arrange dinner with the soignée wife of a chap he was at nursery school with, I realise, not without envy, that to be a Venetian is to live in the world's most beautiful and sophisticated village.’ (Oxford Dictionaries)