It is recommended that you dress in "business casual" for NPHC events.
Below are some recommendations regarding "business casual."
Khaki pants, neatly pressed, and a pressed long-sleeved, buttoned solid shirt are safe for both men and women. Polo/golf shirts, unwrinkled, are an appropriate choice if you know the environment will be quite casual, outdoors or in a very hot location. This may not seem like terribly exciting attire, but you are not trying to stand out for your cutting edge look, but for your good judgment in a business environment.
Shoes / belt:
Wear a leather belt and leather shoes. Athletic shoes are inappropriate.
Ties are generally not necessary for business casual, but if you are in doubt, you can wear a tie. It never hurts to slightly overdress; by dressing nicely, you pay a compliment to your host. You can always wear the tie and discreetly walk by the room where the function is held; if no one else is wearing a tie, you can discreetly remove yours.
Long-sleeved shirts are considered dressier than short-sleeved and are appropriate even in summer. Choosing white or light blue solid, or conservative stripes is your safest bet. Polo shirts (tucked in, of course) are acceptable in more casual situations.
Wear dark socks, mid-calf length so no skin is visible when you sit down.
Leather shoes should be worn. No sandals, athletic shoes or hiking boots.
Just as with interviews: Facial hair, if worn, should be well-groomed. Observe men on campus if you are unsure what's appropriate or are considering changing your look.
Wear a conservative watch. If you choose to wear other jewelry, be conservative. Removing earrings is safest. Observe other men wear around campus to see what is acceptable.
Don't confuse club attire with business attire. If you would wear it to a club, you probably shouldn't wear it in a business environment. Also, most attire worn on televison is not appropriate for business environments. Don't be deluded.
Women can wear casual pants or skirts. Neither should be tight. Fabrics should be crisp; colors should generally be solid; navy, black, gray, brown and khaki are always safe bets. For the most business-like appearance, pants should be creased and tailored; neither extreme of tight or flowing. Observe well-dressed women on campus for further consideration.
Skirt length and slits:
Your skirt should come at least to your knees while you are standing. While you are seated, your thighs should be covered. If your skirt comes to just below the knee, a slit to just above the knee might be acceptable. A very long skirt should not be slit to above the knee. Generally slits in the center back of a skirt — to facilitate walking a stair climbing — are acceptable. Slits to facilitate a view of your legs are not appropriate for business purposes. Slips should not be visible.
In addition to tailored shirts or blouses, tailored knit sweaters and sweater sets are appropriate business casual choices for women. Cotton, silk, and blends are appropriate. Velvets and shimmery fabrics suitable for parties are not appropriate. Fit should not be tight. Cleavage is not appropriate to business and job search occasions.
Wear a conservative watch. Jewelry and scarf styles come and go. Keep your choices simple and leaning toward conservative. Avoid extremes of style and color.
Keep makeup conservative and natural looking. A little is usually better than none for a polished look. Nails should be clean and well groomed. Avoid extremes of nail length and polish color.
Should be leather or fabric / microfiber. Appropriate colors are black, navy and brown (to coordinate with your other attire and accessories); white and pastels are not appropriate. For the most conservative look, toes should be covered. Sandals which are neither extremely dressy or extremely casual might be appropriate. Thin straps and high heels are not appropriate. Chunky heels and platforms are not apropriate. Make certain you can walk comfortably in your shoes.
Not essential for business casual, but are recommended if your skirt is knee length (rather than calf length).
If you carry a purse, keep it small and simple, or carry a small tote bag in place of a purse. A structured bag tends to look more professional that something soft or floppy. Purse/bag color should coordinate with your shoes. Leather, microfiber and fine wovens are appropriate. Canvas and straw are not appropriate.
*Many of these recomendations taken and adapted from Virginia Tech Career Services department