There is a tension in men's dress, a tension between looking good and looking as though one did not spend time considering how to do so. The tension arises because for centuries the male ideal was the man in a military uniform cut to perfection. And though military officers' dress regulations have usually given their wearers a great deal of latitude, the presumption was generally that men in uniform were wearing ensembles that they could don blindfolded because everything had been specified for them.
Carried over to civilian clothing, the ideal has traditionally been that a man should not look too "put together," a state that might apply to a basic combination like a navy suit, light blue shirt, mid-blue necktie, and a patterned blue linen pocket square where every element relates to or matches everything else.
The simplest way to avoid looking too put together is to minimize repetition of colors or patterns in the day's dress, where an example might be a gray flannel suit worn with a white shirt, navy necktie, and a white linen square with a maroon border. Or, consider a combination similar to the one in the photograph: tan suit, light blue shirt, brown and ivory necktie and a maroon linen square with white dots.
It takes thought to arrive at an unstudied look.