Summarize the following:
While it is nice to think that an expert in particular should be able to identify a dog's breed makeup just by looking over the animal, this method is not the most accurate.  One study on visual dog breed identification found that even self-described "dog experts" were only able to correctly identify a predominant breed in a mixed-breed dog about 27% of the time.  Regardless of accuracy concerns, however, identification by visual appearance is the most likely method for use by the average mutt owner, and often sufficient to satisfy a general curiosity.  Best of all, it's free. Make a list that ranks your dog's distinguishing features from most to least prominent (such as large, pointy ears versus average build). This will help you narrow your search for likely breed(s). If you don't have a pet scale, weigh yourself and then weigh yourself holding your dog. The difference between the two weights is the weight of your dog. Of course, you can also get your pet’s weight at any veterinary office.  Take measuring tape and measure your dog from front to back, top to bottom, and left to right. These general measurements will allow you to rule out breeds that are drastically different from your dog. For instance, if your dog weighs 50 pounds, you will know that you don't have a small toy breed. Toy dogs (5 – 10 pounds) may include Chihuahuas and Shi Tzus, for instance; dogs in the middle range (10 – 50 pounds), may perhaps be terriers or spaniels; large dogs (50 – 100 pounds) could be setters or retrievers; and dogs over 100 pounds likely have some element of Saint Bernard, Mastiff, or other giants in their breed mix.  If your dog is a puppy, seek out an online calculator that will let you use puppy age and weight to estimate adult weight. Make note of any defining characteristics you notice. Do you have a large, medium or small-framed dog? Deep chested? Is your dog more muscular or slender in build?  If you have a puppy, you may have to wait until it is fully mature for all characteristics to become apparent. Think about what the build of your dog might mean about its skills. This may help you narrow down the breed group. For instance, if your dog has long legs and is slender, your dog may be a herding dog. Look at your dog's snout, skull, back, legs, and tail, and note any distinctive elements.  Dogs like Pugs and Bulldogs have round skulls and very short snouts (brachycephalic), whereas Collies and Greyhounds have long snouts and narrow skulls (dolichocephalic). Mesocephalic dogs have skulls that most of us think are balanced (not exaggerated), like that of a Labrador or an Australian Shepherd. Visit How to Identify Your Adopted Mutt for several examples of physical characteristics that can often be tied to certain breeds or breed groups. Is the fur long or short or heavy with undercoat? Is the texture coarse or soft? Some breeds, like Dachshunds, have long backs and short legs and three different types of fur-coat: long, short and wiry. Other breeds only have one type of fur, like the short semi-spiky velvet of the Chinese Shar-Pei breed or the white fluffy fur of the American Eskimo breed. There are a wide variety of types of dog fur. Rottweilers tend to only have short black and mahogany fur with specific markings on the head and chest. Many (not all) terriers have wiry coats with short, stocky bodies like that of the Cairn Terrier, the Miniature Schnauzer and the Jack Russell (aka Parsons) terrier. Poodles have the distinction of having curly coats of springy curls in a variety of sizes and colors. What color is the fur? Is there a pattern to the coat color? Some breeds typically come in only one or a few colors or patterns, which may help narrow the possibilities. For example, German Shorthair Pointer dogs usually come in liver and white and Vizslas are a solid copper color. There are breeds that also come in a merle pattern where diluted black or red colors are mixed in with white like the blue merle Australian Shepherd or Shetland Sheepdog. "  No matter how detailed your description is, you'll never be able to make a completely accurate determination of your dog's breed.  However, with the help of one or more dog breed description guides, you can at very least eliminate many possibilities.  There are numerous online options for dog breed searches, which use photos and brief character trait descriptions to help you find matches for your mutt.  Some also break down the categories by dog size, from "toy" to XL.  The American Kennel Club (AKC) breed search, for example, provides images and brief descriptions of characteristics common to each breed.  Eliminate breed groups that don't fit your dog's characteristics. After that, go through pictures and descriptions of breed groups that are similar to your dog. Remember that your dog is quite possibly a mix of several different breeds. If your dog has some striking characteristics that match a breed, but it doesn't match completely, it may only partially be that breed.

Summary:
Accept the limitations of visual identification. Write down your dog's defining characteristics as you identify them. Determine the dog's weight and height. Assess the build of your dog. Look at other physical characteristics. Evaluate the fur. Assess the color of your dog. Use the visual clues you have recorded to search for breeds and make your "best guess.