As the saying goes, you can't teach an old dog new tricks. Some tricks, however, are so simple that even an old dog or new puppy can learn them. Just practice any of the following a few times a day with your dog.
One of many simple dog tricks is the basic paw shake. Start with your dog seated, then take his paw and say the word, "Shake." Hold his paw and shake it, then release. As you release, say, "Good dog!" Give him a treat promptly. For added fun, use the word "Howdy" as you shake his paw. This encourages him to begin offering his paw in response to this word as well.
Begin with your dog lying on his belly, then gently roll him over on his side. Say, "Go to bed!" as you press his head toward the floor. Keep him down for a few seconds, then say, "Wake up," and release him. When he gets up, reward him with a treat. For even more impressive results once the basic trick has been learned, train your dog to roll to his side on a more dramatic signal, such as pointing your cocked finger at him and saying the word, "Bang!"
Place a box of tissues on the floor, and place a treat on it to encourage your dog to pick up the box by placing a treat on it. Once he picks it up, call him over to you and give your usual command to drop an item, so that he drops the box next to you. Practice this a few times to begin, then start saying "Give me a tissue," or simply "Tissue," when he drops the box, causing him to associate all three tasks with that single command. As a cool extension of this trick, try making your sneezes sound like the word, "Tissue!" so that your dog fetches you a box of tissues whenever you sneeze.
Begin by saying the word "Sing" and singing to your dog in a high-pitched voice. Avoid using words in your singing, and stick to simple monosyllables, such as "La" or "Ha." If your dog does not respond, try changing your pitch or length of notes to encourage him to sing along. Remember to say the word "Sing" each time you sing. If he seems to need a bigger hint, you can even howl to him after saying "Sing." When your dog responds with howling, reward him.