Many of us would know about hiring a graphic designer to deal with all the marketing collateral needs, and often considering them as Jack-of-all-trades able to cover everything that you need. There is no doubt that most designer are able to handle most of it, but layout designer is more likely the person that you rely on the most.
Graphic design thus break into various discipline according to the component of a marketing design piece requires: you need a copywriter to get your content right based on the given brief done by the creative designer. The text can only be used after it is being edited by copy editor, who is often being the child who lead the design team. A photographer or illustrator will then work together with the layout designer to produce the design piece with the best raw material produced, then it is again check by the communication designer to ensure the correctness of the piece as it adhered to what is required in the brief. But without substantial budget allocated, it often left with the layout designer and the client only.
A newsletter or any form of publication would require careful planning. A careful proofreading is essential too to avoid any error that slips out when it is being published. These are often the post design job that got omitted simply due to the lack of attention to details.