What sets prime quality meat apart is the fat. 
Though health-conscious Americans are cautious about fat, it is everything to prime beef, unlocking more flavor and better texture.
Marbled meat has fat finely speckled throughout it which will keep the meat fibers from tightening up during cooking.

When purchasing steak, look for steaks that look like 
the below photos.

You may want to research about aged steak, different 
cuts, about cattle raising and feed, availability, etc.

Beef Tenderloin -The Fillet Mignon Also called the chateaubriand, the difference is the size, fillets are smaller. This steak comes from a cut called the tenderloin which, as the name suggests, is a very tender cut of beef. The meat is lightly marbled but is considered the "King" of steaks. 
The "Kansas City" or "New York" strip. The difference depends entirely upon your location; they are the same cut of beef. This comes from the strip loin and is a fairly well marbled cut with a border of fat along one side. It is the best steak for cooking on the grill.  
T-bone or a Porterhouse consists of a fillet mignon and a strip steak with the bone (shaped like a "T") that separates the two cuts. 
The Rib Eye steak. A rib eye is normally cooked as a roast and then called "Prime Rib" when you cut it into a steak you get a steak that is heavily marbled with a large seam of marbling running right through the center. It is one of the most flavorful steaks you can have. 
The Top Sirloin. Also known as the top butt, round, or rump steak, can also be found on menus as a London broil. This meat has full flavor but not as tender as other steaks. Use to cut into cubes for stir fry, stews, and especially, shish kabobs. The secret to a London
broil rump steak is to slice it into very thin slices after cooking then dredge them in their pan dripping juices with some salt and pepper added in it before serving.

How to tell if your steak is going to taste good? 
There is only one visual characteristic that can be used to determine the tastiness of beef, and that characteristic is marbling. Marbling is the amount of fat that is inside the meat, it is those flecks or seams of white that are speckled throughout a steak. The more marbling, the better the taste, in the US we have a quality grade system to label this aspect. The scale is Prime, Choice, Select, Standard, etc... Prime is of course the best. Only 2 % of all US beef is graded Prime. 
Meat that is heavily marbled does not increase your cholesterol any more than beef that is lean. The fat that is within the meat (marbling) on beef and the fat that surrounds the meat ("bark") are two different types, the marbling is not so bad for you, the bark is. So you don't have to eat tough, tasteless beef to feel healthy.

Broiling - Grilling a Steak Tender


 1-1/4" to 1-/12" Thick
Fillet Mignon Steaks