A good bed throw has weight to it before you even pull it over the comforter, enough heft that it stays put instead of sliding off into a puddle on the floor every time somebody turns over at two in the morning. It should feel cool and a little slippery under your hand for the first second, then warm up fast once it settles. And it should land on the bed with a soft thump, not a crinkle, which tells you more about what it's made of than any tag will.
If you've got none of these and you're starting from zero, go with something mid weight in a knit, cotton or a wool blend, rather than anything too precious. A chunky knit throw in a plain color does the most work for the least fuss, it covers the end of the bed, it photographs fine if someone wanders in with a phone, and it doesn't fight with your pillows or your headboard the way a patterned one can. Save the fur look or the heavier wool for round two, once you know what you actually reach for on a cold night versus what just sits there looking nice. Size is where people get it wrong most, and I did too, I bought a throw sized for a queen and put it on a king for about a year before I noticed it only covered two thirds of the bed and looked like an afterthought. You want it to drape past the sides by a good eight to twelve inches and still have enough length to fold back at the foot, so measure the actual bed, not the mattress, because a thick topper or a tall frame eats into that drop more than you'd expect. Too small and it looks stingy, too big and it drags on the floor collecting dust and whatever the cat's been doing all day.
What separates a throw you keep for ten years from one you're folding into a donation bag by spring comes down to how it's finished at the edges. A well made one has a hem that lies flat, stitching you can't easily pick at with a thumbnail, and a weight that's even across the whole thing rather than heavy in the middle and thin at the corners where it was clearly cut to save fabric. Cheap ones pill within a month, especially anywhere they rub against a duvet cover, and they go thin and see through at the fold lines first, which is usually where you notice it's time to stop pretending it still looks good.
Next time you're holding one, skip the color and feel the hem first.