No other combination of colours throws me into ambivalence and trepidation like black and blue. Navy blue, to be exact. A black suit and a navy blue tie to be more precise. At first glance they seem incompatible, especially because the navy blue tie tends to be obscured by the black suit. To the style novice the pairing of these two colours can be an expirential exercise steeped in aesthetic and visual mendaciousness. A lack in confidence can render it a sartorial aberration. However as dull and incompatible the combination may appear to be, there are ways to make it work, and give it a dégagé look.
First, pattern mixing.
The more patterns you mix, the less offhanded the combination will look. It even speaks volumes about your style if you're going to mix patterns that don't belong in the same family.
Secondly, a shirt can allow for greater experimentation. Think about the myriad colours black and navy can be effortlessly combined with. Pink, purple, lavender, blue, etc, if you in any way find yourself in a state of flummox, then a white shirt is your best and safest option. Any tie you wear with any combination or pattern of blue will look good against a back-drop of a white shirt.
This combination needn't be difficult to pull off, all you need is practical know-how and loads of confidence. Especially in the given context of black and navy blue being amiable colours. Conversely, I find the combination of a navy blue suit and a black tie, quite addling. But that's another post for another day.
PG: Man to man, generation to generation.