The Color:
Dark colors such as blues, grays, and black are the most acceptable for an interviewing suit. Brown is considered a "weak" color.
The Style:
While double-breasted suits have worked their way into the business world, the best choice is still a single-breasted suit. A sport coat is NEVER acceptable.
The Material:
The fabric you choose for your suit is also important. One hundred percent wool suits will wear better and breathe better than suits made of synthetic fibers. "Tropical wool blends" are fine. Avoid one hundred percent synthetic fiber suits because these will look cheap and will not wear well. Be sure to buy a high quality suit in whichever style you choose. It is better to have fewer high quality suits than to have many suits that look cheap.
Here is an example of a good interview suit.
The Color:
The absolute best choice for an interview shirt is plain white. Shirts with pinstripes are acceptable, but not really first choice. A white shirt conveys honesty, intelligence and stability. It should be your first choice.
The Material:
Cotton should be the choice of fabrics when it comes to buying dress shirts, particularly 100% cotton. Cotton shirts will hold up under perspiration better than shirts made of synthetic fibers. Avoid the wash and wear instructions on the label and have your shirts PROFESSIONALLY CLEANED AND STARCHED. Although you may not find heavy starch extremely comfortable, it is most appropriate for an interview. Button down shirts are the best choice, but the most important thing to remember is to get the shirt professionally starched. A good interviewer will recognize the wimpy cuffs that accompany a home ironing job.
The Style:
The tie is your opportunity to show your personality, within limits. Wear a tie that complements your suit, and that you feel comfortable wearing. A 100% silk tie is best. The most popular and safest styles are found within the categories of solids, foulards, stripes and paisleys. Do not wear bow ties. A bow tie has its place, but the job interview is not it. Also, don't wear ties with large polka dots, pictures of animals or sporting symbols (such as golf clubs). I once had a student who wore a fish tie to a Big Six firm interview!
The Length:
A tie should extend to your trouser belt, with the front of the tie always being longer than the back of the tie. Different tie knots exist, but smaller is better.
The tie on the left is an example of a tie that is too long. The tie on the right is too short. Once again the tie should reach to your belt line, no longer.
The Material and Color:
Your dress shoes should preferably be black leather; ox blood is also acceptable. Stay away from all other materials and colors: they are too risky. Make sure your shoes have a nice SHINE to them. Use an instant shoe shine pad when you're running late and don't have time to give them a polish.
The Style:
Lace-up wing tips are the most conservative choice and are almost universally acceptable. Slightly less conservative, but still acceptable, are plain lace ups or slip-on dress shoes- not to be confused with boating shoes. The slip-on (with its low, plain vamp or tassel) is versatile enough to be used for both day and evening business wear.
Socks should compliment the suit; accordingly, they are likely to be
blue, black or gray. They should be long enough for you to cross your legs
without showing off bare skin or leg hair! The sock should not fall in a
bunch toward the ankle as you move. Elastic-reinforced, over-the-calf
socks are your best bet.
The undershirt is a must. Stay away from v-neck and tank top
undershirts. Wear a traditional short sleeve white undershirt with a round
collar. No iron man sleeveless tank undershirts!
Notice in the picture below the shadow of the v-neck shirt underneath. This looks foolish.
Jewelry:
Men may wear a wedding band, if applicable, and a small pair of subdued cuff-links (if wearing French cuffs, of course). ANYTHING MORE IS DANGEROUS. Fraternity rings, bracelets, neck chains or medallions can send the wrong message. You should also never wear an earring to an interview!!
Cologne:
Do not wear cologne. Some people are allergic to cologne, while some just do not like cologne on men.
Facial Hair:
Many men and women do not like facial hair, and some are even offended by it. It is best to shave before your interview. Once you have the job and can assess the facial hair environment at your company and then you can decide whether or not to grow a mustache. Beards are rarely acceptable in the business world.
The Haircut:
Get a short haircut with short sideburns! If this makes you look too young, consider buying a pair of glasses. Fake glasses will make you look older and more professional.
Accessories:
Buy a high quality black leather portfolio to carry copies of your resume, paper, pen, etc.