Professional Business attire specifics for men: 

• Suit:
  A two-piece matched suit is always the best and safest choice. Don't combine a suit jacket with pants that don't match.
• Conservative colors / fabric:
  Navy and dark gray are safe and are the most conservative for men. Black for men was once considered severe or overly formal, and may still be considered so in very conservative industries, although it is commonly worn by many. Other color trends may come and go; avoid the extremes. Choose a solid or very subtle weave pattern or plaid (the kind that look solid across a room). Wool, wool blends, or very high quality blends with natural fiber, are the only acceptable fabrics for a conservative men's suit.
• Cost / quality:
  You are not expected to be able to afford the same clothing as a corporate CEO. Do invest in quality that will look appropriate during your first two or three years on the job. One good quality suit is sufficient for a job search if that is all your budget allows. You can vary your shirt and tie.
• Ties:
  Tie styles come and go. Select good quality silk ties.
  Avoid fashion extremes, like character ties, in interviews.
  Notice what men in your industry wear on the job, at career fairs, at information sessions, when they meet with clients.
• Shirts:
  Long-sleeved shirts, even in summer. Choose white or light blue solid or conservative stripes.
• Socks:
  Dark socks, mid-calf length so no skin is visible when you sit down.
• Shoes:
  Leather, lace-up or slip-on business shoes, preferably black or cordovan. Invest in a good pair; even if you don't wear them daily on the job, you'll need them for other occasions and you should expect to get lots of years out of good shoes.
• Belt:
  Black or cordovan leather, to match your shoes.
• Facial hair:
  If worn, should be well-groomed. Observe men in your industry if you are unsure what's appropriate or are considering changing your look.
• Jewelry:
  Wear a conservative watch. If you choose to wear other jewelry, be conservative. Removing earrings is safest. For conservative industries, don't wear earrings. Observe other men in your industry to see what is acceptable.
• Details:
  Everything should be clean and well pressed. Suits typically have tacking stitches to hold vents on the jacket back and on sleeves in place before the garment are purchased. Cut them off if your retailer / tailor doesn't. And that tag stitched on the outside of your sleeve is not meant to stay there like a Tommy Hilfiger label cut it off! Carefully inspect clothes dangling threads, etc.