Non-verbals go beyond what your facial expression is like and your body posture and position. Clothing says a great deal about who you are. Make sure you are memorable because of two things: you make the client/other person feel comfortable by matching them in their attire AND always remember: elevate by 1%. That 1% could be as simple as a gentleman carrying a white pocket-handkerchief or for women: a fun shoe color that pops your outfit and, oh wow: conversation. (Don’t worry: It doesn’t have to be 4 inches tall to attract attention; some of the cutest shoes are colorful flats!)
I recently worked with clients who call on farmers and agricultural specialists. They make tab-front short sleeve shirts and button-down long-sleeve shirts look cool, casual and professional while still being highly approachable to true out-in-their-fields farmers. And the women with them: a nice neck scarf with good color, or a tailored sweater-jacket was perfectly suitable to command the meeting while also being casual enough to not be off-putting