Being a client, what information should I provide to help improve my LSP's translation quality?

Clear and concise translation requirements are the basis for an LSP to provide high-quality translations. We appreciate if the client can clarify the following requirements: Does the document need to be literally, freely, or creatively translated? Are there a style guide, TM, and glossary available? Are there special requirements on document layout? etc. High translation quality is not a sole responsibility of an LSP, but resulted from the joint efforts of both the LSP and its clients.