Televisions have long been a staple of Black Friday deals. Amazon (NASDAQ:AMZN), Best Buy (NYSE:BBY), Walmart (NYSE:WMT), Target (NYSE:TGT), and others all offer a variety of well-priced TVs. In fact, if you enter any of the brick-and-mortar chains on the big shopping day (or on Thanksgiving itself), you're likely to see televisions of various sizes stacked all around the store.

Buying a TV on Black Friday may not be the deal it once was only because the price of flat-screen televisions has fallen. It was not that long ago when getting a 32-inch television for under $300 was considered a good deal. Now, it's possible to find bigger screens for under $100.

Still, Black Friday does offer some tremendous television deals, but you have to know what you're looking for and do your homework. If you just walk into Best Buy, Walmart, or Target, or jump on a seemingly good digital offer from any of the three or Amazon, you could end up making a big mistake.

People point at a TV.

Black Friday is full of big-screen TV deals. Image source: Getty Images.

Decide what's important

Are you someone who wants the sharpest picture possible, or do you just want the biggest possible screen? Does sound quality matter to you, or are the aesthetics of the set your biggest concern? Do you want built-in smart TV functionality so you can watch various streaming services without using a secondary device, and do you have a preference as to which "smart" technology the TV uses?

When buying a TV, everything is a trade-off. The cheapest sets will have the worst specs and generally not be as pretty, with larger bezels and less-sharp lines. Prices also tend to go up as screen size does, but a high-end 40-inch television with top-tier specs may cost more than a bargain-basement 52-inch screen.

Know what you're getting

All of the above can make buying a TV confusing. Will you notice slightly lower resolution? Is a bigger screen worth sacrificing having built-in smart technology?

Those are personal choices, and most people have a little bit of wiggle room. Basically, you need to decide the least you're willing to settle for, and then start shopping.

Once you start looking at TVs, you need to do a few things. The first is make sure you're comparing apples to apples. Sometimes different retailers will use slightly different model numbers, or will sell special holiday models that have similar model numbers but not the same features as the regular model. That forces consumers to really look at the specs to make sure they're getting what they think they're getting.

It's also never a bad idea to see the set you intend to buy in person, but looking at a screen in a big-box store may not be that useful. Make sure you read consumer reviews on the exact model you plan to buy. If a lot of people have complaints, that may be a reason to stay away (unless the complaint is about a feature you don't care about).

Price, price baby

The goal is to get as much TV as you want/can get for the least amount of money. That does not mean you should buy the cheapest TV. You wouldn't buy an old, rusted-out car that barely runs because it's inexpensive, and you shouldn't buy the cheapest TV unless it's also one that's good enough for your needs.

The good news is that the nature of Black Friday has changed, and while the absolute best deals may sell out quickly, most won't. That means you can take some time (but not too much) comparing what the best deals are across the various stores as well as compare Black Friday to Cyber Monday offers.

Once you find what you want, though, you should make the purchase. It's not that there won't be deals left on Saturday, or even beyond, but the pickings will get slimmer, and some deals are only good on Black Friday.

John Mackey, CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool's board of directors. Daniel B. Kline has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Amazon. The Motley Fool has a disclosure policy.