Perhaps the most common sign that a man lacks confidence in his clothing choices is the monochromatic look, where, for example, a blue suit is complemented by a blue shirt and a navy necktie. It's an easy trap to fall into, and just as easy to avoid.
Men who find themselves dressing entirely in shades of a color need only remember the phrase "blue with gray and gray with blue." In other words, choose a necktie with a blue background to complement a gray suit, and one with a gray (ranging from charcoal to silver) ground to complement a blue suit.
Here, a gray nailhead suit is paired with a navy necktie with gold spots, a blue and white striped shirt, and a very dark blue paisley pocket square. Nothing fancy, but nothing to be ashamed of either.