Spend more on pieces that will last multiple seasons, and items where quality really varies by price range. For example, a basic tee at Gap will cost you $19.99 and a similar one is $8 at Target. The difference in quality doesn't merit the difference in price. On the other hand, certain items like outerwear will have more meaningful quality to price relationships. So, make sure to get the most for your money.
Look for quality in shoes, especially those that are more than just special occasion wear. In the category of footwear, price and comfort are often directly related. Non-leather materials don't adjust to the shape of the foot and will often rub and cause blisters. Cheap heels are often unbearably uncomfortable. Don't worry if your budget is small, if you shop smart you can get great shoes for the price of awful ones, but more on that in a minute.
Look before you buy. If I know that I want something, I start looking for it in a multitude of places online, just to get a feel for variety in style and price range. There are a thousands of variations of the pencil skirt, the blazer, the little black dress. Details do make a difference; get a feel for them before you take the financial plunge.
Browse in person. Start at the highest end and work your way down. See the styles and feel the fabric that cost top dollar. Like I said before, details make a difference. Browsing should be an education; it will help you know quality when you see it. This knowledge is invaluable in recognizing the best thrift store finds and avoiding the pitfalls of cheaply made yet expensive goods (yep, they're out there, in abundance).
And related to the previous tip... Know what real leather looks and smells like, and see the difference between high quality and low quality leather. Similarly, all wool (even 100% wool) isn't created equal. Be aware that there can be huge variations in quality even in the same material.
Look outside the box. Don't limit yourself to the usual department stores. Once you know exactly what you want, hit the thrift stores, resale shops (like Clothes Mentor), consignment shops, ebay, etsy, and estate sales (great for unique accessories!).
Some people are weirded out by "used" shoes, whether from the thrift store or a consignment shop. I encourage you to reconsider this position. I have often seen like new or new with tags shoes in such places, so it's worth a look. I would advise you to avoid anything that has signs of wear or was cheap to begin with.
Check the clearance racks. As far as regular retail, I have often had excellent luck with the clearance rack at DSW. Sign up for the free loyalty program and you will occasionally receive $$ off coupons. I combined a couple such rewards (one issued for my birthday, another for accumulated points from previous purchases) and ended up paying $19.99 for a pair of leather heels that were originally $100.
Buy at the end of the season. Get what you need most urgently, but don't be afraid to start thinking ahead to the next several seasons. Last fall, I purchased a pair of leather sandals from PIPERLIME that originally retailed for $75. Because of drastic markdowns, I paid a third of that price. Is the wool of your winter coat worn? Coats are drastically reduced right now; start looking!
Sign up for email notices from your favorite retailers. Never miss a coupon code or sale. This practice also helps you get a feel for how big and how often sales occur. Such knowledge is key when deciding whether to buy or hold out for a lower price.
Check into store cards. Do you use a credit card frequently? It seems that more and more people are doing so for everyday purchases such as gas and groceries because debit cards are more vulnerable to theft. Let me be very clear, I never recommend going into debt for clothing, or paying interest on credit card balances. Yet, if you regularly use a card and aren't getting much in the way of rewards you might want to look into a different credit card. Gap, Banana Republic, and Old Navy cards offer rewards that can be used for any of those three retailers and Athleta and PIPERLIME, and also special cardholder sales. Other retailers also often offer rewards for in and out of store purchases, so if you regularly buy items in such a place, it might be worth looking into. Please note that store cards often have higher interest rates than other credit cards, but if you don't carry a balance that fact is irrelevant.
Do you have any tips to share with the budget wardrobe builder?