Have a plan. Check your closet and make a mental note of what you could use (e.g., a black turtleneck to go with menswear pants you own, etc.)
1.Set a budget. Knowing you can only pay $100 for a dress ahead of time will help you sort through the racks quicker.
Start early. For special occasions allow yourself at least two weeks prior to the event to find the dress. You'll need extra time for shoes and accessories.
2. Dress for shopping. If you'll be looking for a special occasion dress, try to wear or bring undergarments (strapless bra, etc.) to go with the style. Otherwise, wear easy on/off clothes. Also, styled hair and makeup will make looking at yourself in the dressing room mirror just that much easier.
3.Shop by yourself. If you really need a second opinion, put the item on hold and bring someone back with you later.
Keep a blind eye to sales and promotions. Stores put enticing promotional items at the front. Chances are you'll blow your budget right there unless you stay on task.
4. Accept a salesperson's help. You may be surprised by how much time you'll save you if you'll give them some direction about what you're shopping for.
Try it on. Walk, sit, bend in the clothes. Do they move easily? Are the seams pulling? Do zippers, buttons, etc. all function properly?
5. Use the three-way mirror. Get an honest look at your rear and side views. Watch for extreme panty lines (too-tight pants), bunched up waist (too big) or other tell-tale signs of an ill-fitting garment.
6. Check the care tags. If laundry concerns matter to you, then you may want to do this while browsing. Otherwise, see how much care the item is going to require.
7. Check the return policy. Many stores don't give cash back, just a store credit; but some mark sale items "final sale" which means you can't bring them back at all.
Avoid buying items you can't return for at least a store credit.
Never buy anything that doesn't fit perfectly. The only exceptions are pants/skirts that can be easily altered for length at the hem.
It's not a bargain -- even at 90% off -- unless you actually have some way to work it into your existing wardrobe.
What You Need:
Money: checks, cash, credit cards
A shoulderbag to keep hands free for shopping
Comfortable clothes and shoes for trying on and walking