I need to know your age, physique, and the specific type of business to give proper advice. Plus your location.
But I'll give some general thoughts. I differ with some of the previous posts. First of all, start with shoes. This is as important as the suit itself. You will look best in dress black tie shoes, not loafers, with leather (not rubber) soles. These are called Oxfords usually, wing tip or cap toe are OK but so is plain. They should be as simple as possible, new and well-polished. (In theory you should have thin, waxed laces, but whatever laces come with the shoes will be OK). Plain black loafers can work too.
Socks should be thin, high, and black-on-black pattern (or all black). If you are thin yourself, then you can have a subtle color pattern in the sock, but if you are heavy, no.
Most men look better in a dark navy suit than a black one, and dark navy is more acceptable in some business settings. Belt should be smooth black leather, with a silver or gold buckle depending on which looks better with your skin tone. Silver if you don't know.
Thus the shoes, socks, and belt are black, even though the suit is blue. In general I agree you don't mix blue and black, but this is the exception.
You will again look better in a pale blue shirt, rather than white. It should be solid for sure, and button-down is more acceptable in many businesses than spread color. If you are thin, a spread color can work, but not if your face is fat. Be sure the sleeve length is long enough so that a little shirt cuff shows when you have the suit jacket on.
The tie should be silk, slighty shiny (not too much), basically dark red with some subtle pattern, like blue and white. It should have a slight "pop". Learn to tie a half-windsor (unless you chose a wide spread collar, then go for a full windsor). Not too small and not too big on the knot.
This is the American power look. The British power look is different.
If you are young and not heavy, then a blue pin-stripe suit can work. Or a pin-stripe shirt (but not both). If the pin stripe is subtle enough, the tie can remain patterned with color. Otherwise a very high quality dark red solid, or better tone-on-tone dark red pattern must be paired with the pin-stripe.
This is ultra-conservative. But it is absolutely American classic, and you can't go wrong. Later you can mix in fancier and bolder stuff, but not on a one-suit budget.
Target has amazing quality for very low prices. You can put this entire outfit together there.
