People often choose their dogs based on the breed. Each breed is unique with different features that are suited to different tasks or different areas of the world. As with humans, eye color can vary among dogs, and it's a feature that can be hard to determine, especially when dogs are very young. Often you can't tell for sure what the final eye color your puppy will have until it's between 8 and 10 weeks.
Read up on the breed of puppy. The American Kennel Club boasts an index of recognizable breeds on its website. If you know the breed of your puppy, you can read up on the behavior of the breed's eyes and all of the potential combinations and colors that it can grow into.
Watch your puppy's eyes. As with kittens and babies, puppies are generally born with bright blue eyes. As time goes on and their bodies mature, however, that blue usually changes and turns to other colors, sometimes more than one.
Continue to watch your puppy's eye color until he is between 8 and 10 weeks old. It's around this time that the puppy's eyes should have settled into their final shade of color.