Summarize this article in one sentence.
Puppies can be taught simple commands starting at seven to eight weeks of age. The key to training is to make each session fun and short. A minute or two for each month of age up to 6 months is a good ballpark figure. Trying to do more than that will not benefit you or the dog because his attention span can’t handle it. Reward-based training is one of the most positive and effective way to train your Rottweiler puppy. Positive reinforcement, such as a small piece of a tasty treat or lavish praise, should be given immediately when the puppy obeys the command. Keep a bag of small, tasty treats handy, such as tiny cubes of cheese or very small pieces of cooked chicken, to immediately reward your pup for any steps towards learning the new command or cue.  Once the puppy is consistently obeying your command, the treats can be given intermittently then gradually phased out, replaced with consistent praise. If you fail to reward immediately, the puppy will become confused as to what you expect from her or him. The commands used need to be short, one or at the most two words. Keep your voice friendly. Always praise your puppy for any attempt in the right direction, and absolutely never yell or hit your puppy. Your pup is obeying you because he wants to please you at this point, so remind him that he is pleasing you with his obedience. Each of these principles can be used for all the commands you use for training. The key to the reward system is to reward immediately, be consistent, and use simple command words. The best time to conduct a training session is when the puppy is relaxed and alert. Never train when the puppy is sleepy, wound up, or not feeling well. You want his mind completely on the training session and his attention on you. When you start training your dog, perform the commands for 10 to 15 minutes at a time. During this time period, spread out which commands you teach. Try five to 15 repetitions of one command, then move on to another one and do five to 15 repetitions of it. Once the time is over, reward your pet and praise him. You can do this up to three times a day with different commands. You should also start with shorter time periods he has to stay in each command as well. When you are first teaching him to sit, for example, try to make him sit for three seconds before rewarding him. As he learns, move the time up, increasing until he can stay for 30 seconds or longer.

Summary:
Start early and short. Reward your pet. Learn the right kinds of commands. Be consistent. Train for the right amount of time.