Question

techniques are used exclusively for designing hierarchy?

Answer 1

Things that help designers focus on what's important to a design:

Identify the key message - this is what people viewing the design should intuitively grasp, this is the voice or message of the design. Everything in the design should help reinforce the message. This is a careful balancing act as being too blatant can be off-putting and not everything in a design should be screaming the same message at the same time.

Identify what the design is to accomplish - what are the business needs for the design? Why is someone paying for this? Why should people look at your design? Make sure your design actually helps accomplish the business goals that created it. Otherwise it just becomes personal art.