What to Wear - Everyone

Wear clothes that are comfortable and that make you look great.

Make sure your jacket and shirt fit you well. A poor fitting jacket or shirt will be obvious in the photos (especially around the neck).

Don't overdress.

Turtlenecks are almost always a bad idea (since they crowd the face).

Clothes should be neatly pressed and should look new or like new.

Avoid busy patterns and large lines/stripes.

What to Wear - Women

Avoid big prints and busy patterns

Choose  a  shirts/blouses with neckline, which will influence the apparent shape of your face.

For a no-jacket casual look, choose colored blouse - ideally darker than your skin tone.

Be stylish and fashionable, but remember the picture is about your face and not your clothes or jewelry.

Sleeveless tops/dresses can draw attention to your shoulders/arms. 

A white shirt/blouse/sweater by itself is a bad idea - it draws attention away from the face. Better to wear white under a jacket or sweater.

Keep jewelry simple - small is better. Avoid jewelry that would distract from your face or that looks dated.

What to Wear - Men

The standard business look is a suit jacket, dress shirt and tie.

A casual business look is often a jacket and open-collar dress shirt, shirt and tie (no jacket), or dress shirt on it's own.

For a no-jacket casual look, choose colored shirt - ideally darker than your skin tone.

A white dress shirt by itself is a bad idea (too bright) - unless you plan to wear it underneath something (jacket or sweater).

Hair and Makeup Tips

Make-up should be clean and natural.

Wear a heavy layer of translucent powder - your face will appear flawless in photos. Shine disappears, pores seem smaller, skin looks even, and blush is smoother.

Line lips before applying matte lipstick, then reline. Don't overdo it. 

Avoid shimmers or products with lots of sparkle or shine Avoid frosts or overly-bright colors.

Don't get a new hair cut just before the shoot (you may want to let it grow-in a bit or get used to styling a new cut).

Do not try/use any new product on your hair, face or body the day before or few days before your shoot. In case you have a bad reaction to the product.