Not too long ago I was asked a question on laying out documents that I'd never really thought about before. I guess I've been doing this type of work for so long, the actual design process has become somewhat automatic. However, recently a reader asked "I've been asked to do a newsletter and I have a lot of pictures and graphics I have to include. How do I know what size to create the boxes, so everything will fit?"
When you get a layout project, you generally deal with two possible situations. In the first case, you often do have to figure out how to cram a whole bunch of text and graphics together into a layout and make it look nice. You start by placing boxes into some sort of logical order and then importing the text and pictures. Then you twiddle and tweak to make it all work. Sometimes you have to go back and do some major editing and/or chop out pictures because there is no way to make 10,000 words look legible on one page (or some other unreasonable requirement).
Unfortunately, the reality is that sometimes people have unreasonable or odd expectations of what can be done. Layout software like Adobe InDesign or Quark XPress don't magically make words and pictures look good. The old GIGO (garbage in - garbage out) rule still applies. If you have too much text or graphics to fit on a page, decisions have to be made. Usually unreasonable project requirements actually come down to money, such as "we don't want to pay to print more than 4 pages, but we want 39 articles in the newsletter." So you have to make compromises.
The second possible scenario is that you are tasked to create a newsletter and the clients have no idea what they want, or they have no articles yet, maybe just a few titles. So you come up with a layout that has "dummy" text in it so people can see the layout before they write the articles. Once this sample layout is approved, you can provide word counts so the client can run off and write the correct amount of copy to fit your layout.
With a periodical document like a newsletter, you often end up with a combination of the two situations. First you are given a few articles and graphics and you figure out a layout for the first issue. Once it's approved, printed, and people have decided they like it, you go back and create a template from it for subsequent issues. Then you can assign articles with more definite word counts.