Basic techniques

These are the most fundamental techniques of nen - everything else, including a nen-user's specialized skill, is really based on these most basic manipulations of nen-flow. These are the first skills that are taught to any nen-user. Often, for an experienced nen-user, these basic 'techniques' are second-nature. For example, a beginner must learn to use Ten, and concentrate to maintain it; where as an experienced nen-user will practically always be in a state of Ten, even when they are asleep.

Ten (纏)

Once a person has had their aura nodes opened, they must learn to keep their aura from leaking away from their body. Ten is the process of keeping the nodes open, but also having aura flow through and around the body rather than away from it. Having a shroud of aura surround the body is the most basic defense against the physical or emotional attacks of another Nen-user. Ten also may reduce one's aging; since the energy powering the body is no longer leaking away, one can keep the body from breaking down, thus slowing the aging process. 

Zetsu (絕)

While Ten allows a user to keep aura from leaking away from their body, Zetsu stops the flow of aura from their body altogether. By closing all of their aura nodes, the user is able to stop almost all outflow of their aura. Because the user is no longer surrounded by their own aura, they can become more sensitive to the aura of others. This can be useful when tracking another person, and it will also prevent other users of Nen from noticing them. Zetsu can also be used to restore vitality, since Nen is fully contained within the body. However, since Zetsu involves shutting off one's aura, it can be dangerous since it leaves the body defenseless against any Nen attack. Even the weakest Nen could do massive damage. 

Ren (練)

Ren is a direct application of Ten. Since a user is capable of keeping aura from leaking away from the body, it's also possible for them to have more aura around them without having to worry about losing it. Ren focuses on outputting a high amount of aura and keeping it on the body, expanding the size and intensity of it. This increases the user's physical strength and durability and provides a large pool of aura for any advanced techniques or individual skills they decide to use.