Dumbledore could be the instructor. He might have a special training program in mind for the students. He could teach them about the deeper mysteries of magic, like the secrets of the Hallows or the true nature of the Deathly Hallows. His wisdom and experience would make him an excellent teacher for the students during the summer training.
In a 'Harry Potter Summer Training' fanfiction, perhaps the training is organized by some of the older students who have graduated but still want to help. They could be teaching the younger students advanced dueling techniques. Harry might discover a new aspect of his magic during this training, something that has been dormant until now. For example, he could have an affinity for a type of magic that is rare, like time - related magic. The story could then revolve around him exploring this new power under the guidance of the older students.
'The Changeling' is a notable fanfiction. It focuses on the character development of a new student at Hogwarts, with a plot full of mystery and magic. This fanfiction is great for training in imagining new storylines within the existing framework of the Harry Potter world.
He could work at Weasleys' Wizard Wheezes. He has a good relationship with the Weasley family, and it would be a fun place for him to work, helping with inventing and selling all kinds of magical pranks and toys.
Well, they could use spells like Protego as a form of defense training, making it more like a shield drill in military training. And for offense, they might practice advanced versions of the Stunning Spell in a tactical way.
It could be a former Death Eater who has had a change of heart. This person might see the error of their ways and decides to secretly train Harry, believing that he is the only one who can truly defeat Voldemort. They could teach Harry some of the Dark Arts that Voldemort uses, so that Harry can better understand and counter them.
Hagrid could be a great help. He has a lot of connections in the wizarding world, especially with those related to magical creatures. He might introduce Harry to someone who needs help with taking care of or studying magical beasts, and thus get Harry a job in that area.
It could be Zeus. He is a powerful god and might see Harry as a worthy candidate for training. He could teach Harry about leadership and power control.
By combining different types of magic training. For instance, integrating magical history study with practical spell - casting. So while learning about the origin of a spell, the characters immediately practice it. This makes the training more holistic.
Well, it could be about a young wizard or witch who is sent to learn from goblins. Maybe they study the unique magic goblins possess, like their skills in handling precious magical items. The plot might involve the main character facing challenges in understanding the goblin way of life and magic, and eventually using what they've learned to solve a big problem at Hogwarts or in the wizarding world.