Shopping estate sales — sales that include the entire contents of someone’s home, after a death or because of a move — can be a great way to get a deal on high-end and antique furniture, artwork, jewelry and collectibles, generally at 35 to 40 percent of the original price.

However, there is lots of competition, from both fellow bargain hunters and dealers. Here are tips from estate sale organizers and expert shoppers to help you score that dining set or vintage Fiestaware.

1. RESEARCH BEFORE THE SALE

Many Long Island estate sales are advertised in local newspapers, as well as on websites such as estatesales.net, estatesale.com and lisaler.com, which generally include collections of photos showing the items that will be available for sale. Social media is also a popular way to advertise. Jen Picciano and Lisa Lopez, the co-owners of Deer Park-based Miss Spiffy Estate Sales, also post preview photos on Facebook, Twitter and Instagram.

Some companies have email newsletters that send links to the photo collections directly to your inbox. Madeline Winn, the owner of Full of Surprizes, who organizes sales throughout Nassau County, sends a weekly email with information on upcoming sales to more than 10,000 subscribers.

“The market is so photo driven,” Winn says. “It’s not atypical to have 100 photos per tag sale. People really know what they’re going to shop for.”

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2. BE AN EARLY BIRD

If there is an item that you have your eye on, getting to the sale early will help to ensure you snag it. Furniture, particularly midcentury Modern and French Provincial pieces, jewelry and collectibles, such as Barbie dolls from the 1950s and ’60s and Lionel toy trains, are especially popular, sale organizers say.

“If you really want a piece and you see it, don’t think if you wait until the last minute it’s going to be cheaper,” says Mona Scavo, owner of Tag Sales by Mona, which is based in Baldwin. “If you really want it, come and get it and negotiate the price right there.”

Sale organizers usually leave a sign-up sheet at the house a few hours before the sale and people are often already there, waiting.

“We’ve had customers come at 3 in the morning and camp out,” Picciano says.

3. STAKE YOUR CLAIM

There are often multiple people interested in the same item. Ronnie Wahrburg, the owner of Gold Coast Tag Sales, advises shoppers to try to find out in advance where in the house an item you are interested in is going to be, if you want to check it out first. Otherwise, if you are certain you want it, make sure to tell the person running the sale as soon as possible.

Scavo stresses that it is important not to hesitate.

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“If you have to go home with it, haggle the price right there and go home with it,” Scavo says. “It’s always the things you don’t get that you regret.”

4. NEGOTIATE

Estate sale organizers are often willing to negotiate the price, but most say you will do better by being polite and not declaring that you’ll only pay half of what’s on the price tag.

“The famous line is, ‘Can you do a little better than the price on the ticket?’ ” Winn says. “That’s a respectful way to approach it.”

5. BRING SUPPLIES AND CASH

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Make sure you go to the sale in a large enough vehicle to move furniture. It’s also a good idea to bring blankets to cushion large pieces, as well as rope to tie your car trunk down.

When buying furniture, bring a tape measure and know the width of your doorways and staircases, Scavo says.

Be prepared to haul furniture yourself.

“All [companies] will charge to deliver it,” Lopez says. “Sometimes it can cost almost as much as the furniture itself.”

Most estate sale organizers take credit cards, but bringing some cash is a good idea, says Winn.

“Even if they have to go to the bank to bring additional funds, they would need a third of the price for a deposit,” Winn says.

6. WHEN TO GO FOR BARGAINS

On the first day of a sale, Picciano and Lopez of Miss Spiffy generally don’t offer discounts.

“People always ask, and sometimes we will [offer a discount] on the first day,” Lopez says. “If we know something is hot and something is in demand, we won’t discount it because we’re trying to make money for the homeowner.”

But, as the sale organizers usually have 24 to 48 hours to liquidate the contents of a house, it can pay to wait if there’s not something specific you want to buy.

“The second day is great for bargains,” Picciano says.

7. TAKE A GOOD LOOK

Picciano and Lopez recommend bringing a flashlight and being prepared to dig.

“Some estate sales are held in old houses without the best lighting,” Picciano says. “We supply additional lighting, but sometimes even that’s not enough. And we do set up the items to sell in a nice display, but sometimes there’s just too much stuff and not enough room. We tell our customers there are potential gems in there.”

They also advise shoppers to inspect items for damage, as all sales are final.

Even if there’s nothing in particular you’re interested in, estate sales are good for browsing.

“Sometimes not everything is online, so you should go anyway,” Scavo says.

8. BRING A (WELL-BEHAVED) KID

Dominique Maciejka, the owner of Paper Doll Vintage, which has stores in Sayville and Huntington, has been shopping estate sales since she was a little girl. Maciejka would play a game with her mom in which they would each ask about the price of an item and see who would be given the lower amount. Maciejka usually won.

“If you have a kid, ask them to ask for prices,” Maciejka says. “They’re always going to get a better price.”