For most plants, there really is no special technique. For example, with stem plants, it is as simple as cutting off the part that you want, and replanting it into the substrate.
For other plants such as Anubias and Java Fern, you just need to cut the plant anywhere along the rhizome and re-tie it to a piece of driftwood/rock.
Other plants that spread by runners can be separated at the runners and replanted.
For other plants such as Anubias and Java Fern, you just need to cut the plant anywhere along the rhizome and re-tie it to a piece of driftwood/rock.
Other plants that spread by runners can be separated at the runners and replanted.