The Society for Technical Communication is the largest technical writing association and defines the term as "The process of gathering information from experts and presenting it to an audience in a clear, easily understandable form."
In order for a technical writer to do so, the subject matter expert or SME cannot be ignored. The SME is an important component of the technical writing process. It is usually an expert on the particular subject or the creator of the subject that is being written who is in the role of an SME.
Thus, if there is a document explaining the correct way to use a hair curling iron that needs to be written, the subject matter expert in this case would either be the main engineer of the device or a hairstylist. The technical writer combines the explanation given by the SME with clear writing skills and prepares a technical document.
A technical writer should have a thorough grasp of the subject matter or technology that needs to be explained. There has to be no room for errors in the writing as it may lead to legal complications. To avoid this, selecting authentic research material and a knowledgeable SME is vital.
The end-result of the technical document has to simplify the technology or mechanism behind the subject for the user. The language used need not be flowery or descriptive, but rather, it should be easy-to-comprehend.