Well, Harry Potter masters wandless magic by having intense mental focus and a deep understanding of magical theory. He also gets guidance from some mysterious mentors and has many challenging experiences that force him to develop this ability.
In some fanfictions, Harry Potter uses his strong emotions and willpower to perform wandless magic. For example, in times of extreme danger or when he has a very intense desire to protect someone, he can tap into his inner magic without the need for a wand.
Often, he uses his deep understanding of magic theory. Since he's learned a great deal about magic at Hogwarts, he can apply that knowledge in a wandless way. He might use incantations silently and with just a wave of his hand or a focused thought, as seen in fanfictions like 'The Wandless Path of Harry'. Here, he spends a lot of time researching and practicing wandless techniques based on the spells he already knows.
In some fanfictions, Harry Potter might develop his wandless magic skills through intense mental training. He could practice focusing his magic without the aid of a wand, much like how he learned to control his Patronus. By visualizing the desired outcome clearly in his mind and concentrating his magical energy, he gradually becomes proficient at wandless magic.
One of the most impressive feats could be large - scale teleportation. In some fanfictions, Harry Potter manages to transport himself and others over long distances without a wand, which is extremely difficult magic even with a wand. Another could be instantaneously conjuring complex magical shields to protect against powerful dark spells, all wandlessly.
It can also change the power dynamics between different magical groups. In some fanfictions, groups that focus on wandless magic might be seen as more elite or dangerous. They might have a different set of skills and abilities that give them an edge over those who rely solely on wands. This can lead to all sorts of interesting storylines, like rivalries or alliances between wand - using and wandless groups.
The Ministry of Magic could also be antagonists. They are often very strict about magic use and might not approve of Harry's exploration of wandless magic. They could try to stop him, fearing that it would disrupt the established order of magic that is mostly wand - based. The Ministry officials might see Harry as a troublemaker and try to put him under surveillance or even arrest him if they think he's getting too powerful in wandless magic.
One interesting plotline could be Harry discovering ancient wandless magic spells hidden in the Forbidden Forest. Maybe he stumbles upon a long - forgotten magical grove where the magic is so pure that it doesn't require a wand. He then has to learn how to control this new - found power without the guidance of his usual wand - based magic training.
In some fanfictions, Hermione is able to do wandless magic through intense study and practice of ancient magical theories. She might have delved deep into books that are long forgotten by most wizards, and from there, she discovers the secrets of channeling magic without a wand. For example, she could have found out about the natural energy flows within the wizarding world and learned how to tap into them using just her willpower and magical knowledge.
I also like 'Unleashing the Wandless'. In this fanfic, the main character is an outcast because of his interest in wandless magic. But he soon finds out that there are others like him. The story is about their journey to prove that wandless magic can be as powerful, if not more, than traditional wand - based magic.
One interesting concept is that it allows characters to access magic in a more instinctive way. In some fanfictions, it shows that wandless magic can be more powerful as it doesn't rely on an external tool. For example, a character might be able to perform complex spells without a wand during a high - stress situation where reaching for a wand is not possible.