Puppies begin to learn at a very young age. Teaching starts with their dam and littermates during play at around 4 weeks, so by the time your puppy comes home at 8 or 9 weeks old, she is ready for some basic training. Sitting is one of the first commands you'll teach and the basis for teaching "stay" and "down." Most puppies grasp the "sit" command quickly. Use positive reinforcement such as praise and treats to make learning fun.
Choose a quiet place to begin training your puppy. Use treats your puppy loves that you reserve just for training sessions. Begin teaching when your puppy is alert and ready to focus -- after a nap or before mealtime is best.
Stand in front of your puppy with the dog facing you. Hold a treat between your thumb and forefinger, right in front of your dog's nose. Don't worry if your puppy jumps up to take the treat. Close your hand and start again.
Move the treat slowly over your puppy's head. She will look up to follow the treat. Her head will move back as her nose follows the treat up, putting her hind end in the "sit" position. Give the "sit" command as she sits down. If the puppy backs up and doesn't sit, gently use your other hand on her back above her tail to guide her into the sit position, using the command at the same time.
As soon as the puppy sits, reward her with the treat and praise her. Repeat this several times using the command. Then position your hand in the same way over her nose, but without a treat. Hold a treat in your other hand where she can't see it. When she sits, give her the treat and praise her. Gradually phase out the treat when she sits on command.