Avoid this trap: "If you're brave enough, walk out onto the store floor and look at yourself in those mirrors," she says. "Or make sure it's something you can return," in case it doesn't look the same at home.
2. Letting you touch -- and use -- the merchandise
This one is a favorite strategy with tech stores, Perez says. Think about the layout of an Apple Store, for example.
While it makes sense to test-drive an expensive gadget before you buy it, it's also smart marketing. Psychologically, when you handle the gear, you form an attachment and a sense of ownership, she says.
Avoid this trap: Browsing rather than buying? That's when you want to "avoid displays where you can touch the products," Perez says.
3. Impulse buys at the checkout
This is one many people know about, but it's still worth the reminder. Whether it's the grocery store, big-box store or your favorite boutique, chances are there will be a selection of small, inexpensive items clustered near the checkout, Perez says.
From candy to coffee mugs, splurge for a few items and you can easily add $2 to $10 to your tab, she says.
Avoid this trap: "I basically put my blinders on because they're not going to get me," she says.
4. Sensory temptations
"Recognize that in the brick-and-mortar world, the use of sensuous cues is on the increase," says Paco Underhill, founding president of Envirosell, a retail research and consulting firm, and the author of "Why We Buy: The Science of Shopping."
"Retailers use lighting, touch and smells as a way of getting you to fall in love with something," he says.
And those sensory appeals can be particularly effective if your energy is flagging or your stomach is empty.
Avoid this trap: Don't shop tired or hungry. "I tell everyone if you want to be a really smart shopper, shop at 11 in the morning," Underhill says.
5. Reaching out via email and newsletters
"Signing up for newsletters is definitely something that encourages us to buy," Perez says.
Especially effective: Those notices hawking 1-day sales and limited deals. They create a sense of urgency.
But many times, those sales are extended or replaced by other sales also offering great discounts, Perez says.
And some sites will bombard consumers with emails virtually every day, "and so you find yourself wanting to shop," she says.
Avoid this trap: Unsubscribe. "Better to be the person who drives when you shop versus having the retailer drive you," says Perez.