It seems as though most people don't know how to order a steak. They don't know the difference between the cuts, they don't know the difference in how it's cooked, and they don't know how steak is supposed to be prepared. If you don't know these things, in effect, you're guessing every time you order. With a little help, you can order a perfect steak every time.
Learn the cuts. This is first step to being able to order a steak. Most people know that filet mignon (don't pronounce the -t or the -g) is highly considered, but don't know why. Understanding cuts of meat will help. There are many different types of steak, but some of the most popular are filet mignon (very lean and tender, but with less flavor), sirloin (a little more fat, more flavor), rib eye (the most fat and flavor), and the T-bone or Porterhouse (these consist of the tenderloin and strip loin around the T-Bone; the difference between a Porterhouse and a T-Bone is the size of the tenderloin).
Know how you like it cooked. Unlike other foods, the waiter will usually ask you how you like your steak cooked. Your basic answer choices are: rare (outside is cooked, but the inside is still partially raw), medium (outside is cooked more thoroughly and the inside is cooked, but still slightly red), and well done (outside is charred and the inside is completely cooked through). You can also create a combination of any two of these basic choices to have your steak cooked between two levels, for example, medium rare.
Try many different types of steak. This is the only way that you'll know what you like and don't like. Don't be afraid of trying a rare steak. Likewise, don't let what other people say prevent you from trying one that's well done. The only way to know what you like is to sample them all.
Differentiate between good and bad beef. Several breeds of cattle produce significantly better beef than others. For example, Angus Beef is considered one of the best types of beef around. Likewise, good beef is usually treated for a set length of time before it is sold. Once you have had good beef, you will always be able to tell the difference.
Add sauces, or choose not to. Some people swear that sauces make the steak. However, be wary of strong sauces that overwhelm rather than complement the natural flavors of the meat. Many connoisseurs believe that you should never use sauces with good beef. It's a decision you'll have to make for yourself.
Choose your side dishes. This will vary country by country, but it is usually a good idea to have some type of a starch to complement your meat. For example, many people eat some variety of potato alongside their steak.
Pick a wine. Although many people prefer to drink beer with steak, wine is still the traditional drink to go with beef. Remember, choose a heavy red wine to go with the natural flavor of the meat.
If you've never been to the restaurant before or are unsure about what to order, ask your server. Chances are they'll know the menu and what the kitchen does well. This means you're far more likely to get a good meal than if you simply guess.
Be wary of ordering a steak well done. Chefs often believe that cooking a steak for that long ruins the meat. So, they'll often pass off old or scrap pieces of meat as it's much harder to tell the difference than it would with a piece of meat that was less thoroughly cooked.