I'm constantly stressing the importance of approachability to my clients, potentials and almost anyone who will listen.
Many people seem to think that black is the catch-all for formal occasions: weddings, dates, interviews, and funerals alike. I think assuming the same attire for your interview and your funeral is a pretty bad start. With the exception of the legal profession, black/white tie events, and bespoke customer service, we never advise our clients to wear black in a professional setting.
This is the margin between good and great if you're looking to be an excellent visual communicator. Color and texture are significant markers in the predisposition of approachability. Black is a cold, closed color and you will seem distant or rigid in your communication. Opt for browns, blues and grays instead as your primary base for suiting, skirts, separates and shoes.
Texture also plays a significant factor. Have you ever wondered why tuxedos have a satin lapel? Black is formal, shiny black is very formal. So in the business world, a silk tie is more formal than one with a flat finish and more formal still than a knit or tweed tie. In terms of approachability, you can quickly move in either direction based solely on the texture of your clothing.