Its said that first impressions are lasting, so it makes sense to have your Linked-In or business headshot be the best it can be. Consider hiring a professional portrait photographer to help you get a nice flattering portrait, so you can put your best foot forward.
As a professional portrait photographer in NY City, I feel strongly that its always better to smile than be too serious for the simple reason that unconsciously we react positively to a smiling face. Also recommended is to wear a dark jacket because visually it contains the image and focuses the viewer’s attention on your face.
And third, decide if you want your headshot to be done in a studio with lighting and a backdrop, or if you’d like your business portrait to be taken outdoors for a more casual look. Both styles of executive headshots work well, its just a matter of which style suits you.