The most important technique is to stay hydrated. You and everyone else. Really.
If you take a reading, as is, off a white building, remember that the meter thinks it is looking at a mid-gray subject. You will have to open it up 1-2 stops for it to look bright mid-day white and not gray. Bracket the exposures.
On the overexposure end, watch out for blown highlights. Chimp a lot if the LCD on back of camera shows hot spots. My D70 does and it is easy to use.
White buildings are all shades of white but you think they are all the same. If you want the building to look white, use it to set white balance, not a color card or gray card.
You can take advantage of that harsh downward light by looking for angles that would benefit. For example, white painted wood on a vertical wall can look pretty flat if light comes from the front. If light comes from above at a slight angle, you might be able to show some relief caused by the wood grain or multiple old coats of paint. Also works on brick, stucco, other low relief textures.
Top light can be used beneficially with polarizers, too, which give maximum effect at 90 degree angle from light source. If it is windy, you can get good saturated flag photos.
Look for sharp shadows to shoot.
It may be too bright and require too fast a shutter or stopping down too much. Use a low ISO. Use polarizer at minimal effect as a neutral density filter. May need a neutral or graduated neutral density filter to lower light levels.
May need highlight and shadow exposures that you then merge in Photoshop to capture bright and dark details.
May need a diffuser screen and reflector to soften the light on a person. Richard Avedon used the side of buildings in his great American West series. Look for broad overhangs in mid-day. Check out
http://www.digitaljournalist.org/issue0406/wilson.html and definitely click on the Gallery link after the text. You will see Avedon and team at work.
And finally, hydrate.
Bill