First things first: you must instantly start calculating how much you really need certain luxuries like cable, water, groceries, etc., so you know how much money you have to invest. Next, you need a POA (plan of attack); sales can be extremely overwhelming and you'd hate to passout while shopping and have someone else grab that $100 must-have Diane VonFurstenberg dress. Finally, dress in something comfortable that is easy to get on and off, so you can easily shophop from dressing room to dressing room. I feel it is my responsibility to act as your safari guide and help you survive the wilderness (have you seen the way some people get over the last pair of $150 Manolos?). Now, it's time to forumlate the aforementioned POA.
For those in the D.C. area, Tysons Corner Center (I and II) is going to allow you to cover the most territory in the shortest amount of time. Personally, I would start at Tysons II because I have found the Neimans and Saks sales will get you the most shopping bags for your(what was formerly known as rent) money. The other big department stores like Nordstrom, Macys, Bloomingdales, and Lord & Taylor have big sales as well, but the margin of savings isn't the same and thus not as exciting.
When approaching a sale rack there are a few things to keep in mind.
$Know what you have in your closet and what pieces/colors you would like to have; it helps to have some guidance as to what racks you need to scour first, so you don't waste time looking through a bunch of jeans when your closet is seriously lacking in the dress department.
$$If you're an experienced shopper you know what brands/designers you really like. Some stores will sort sales racks in this manner, which can save a lot of time; however, since many of the items are so cheap it doesn't hurt to branch out and try something new, especially if something happens to catch your eye.
$$$Always at least skim through all the sizes; people get a little crazy when things are over 40% off and everything gets jumbled up (my success story of the season came from the Size 11 shoe aisle, when I'm normally an 8...an amazing pair of patent leather Gucci heels for under $200!). Also, don't forget that clothing can be altered and it may be worth it depending on the markdown. BUT, as I have mentioned before DO NOT squeeze into something that is too small just because it's cheap.
Now that you're ready to feign sick and leave work early, here's my last bit of advice. Take a trusty shopping buddy along; it's always helpful to have a second opinion to tell you that you really don't need that sparkly sequin Tory Burch dress that weighs 15lbs. Also, it's kind of fun to laugh at some of the really awful high-end designer pieces that you know why they are on sale and people might think you're crazy if you're laughing hysterically alone. Make sure that your pal can keep up, though, or else he/she may get abandoned in a heap of last season's Juicy pants.
Good Luck!!!