A very frequent weakness in many texts is that they contain too much irrelevant information at the cost of the information the reader is interested in. On a similar note, many texts contain important information, but unfortunately not the information readers need in order to best make sense of that useful information.
Inappropriate selection of material for a text makes for a text that does not communicate well at all. This kind of text wastes the time of both the reader and the writer. Reader-orientation is particularly important as you need to identify what is relevant for your intended audience.
Consider the following aspects:
What information is useful and clear for the reader?
You have to discriminate from the material available. Remember that the needs, interests, and convenience of your reader inform the decisions you have to make as a writer. For this reason, you may have to omit a great deal of information simply because that material is not important or does not make sense to the reader. You also have a specific purpose in your text; for example, you might want to answer a specific, narrow research question. You need to be critical in determining which results are relevant to that question and which results, although perhaps interesting, are not relevant and should be omitted.
Critically selecting material requires planning, as you might potentially use this information in different ways. For example, as writers you make decisions about what information to read in order to support your writing. You may have read more broadly in preparation for the writing task, but will only include narrow aspects from that reading in your own writing. Perhaps some of those articles become support for arguments in your own writing. However – the whole article might not be of interest to your readers. Your readers might only be interested in something specific from that article – e.g. a certain result, a method, etc. It is your job as a writer to determine what is relevant for your readers.
How much time does the reader have?
The amount of time available to the reader determines the level and the amount of detail in the text. A reader at a high managerial level, for instance, would expect recommendations and conclusions rather than the details of the argument. However, a reader who will be implementing a suggested process alteration needs a great deal of detail and will be prepared to spend a lot of time reading and re-reading the text to get at that information.
How much information does the reader need?
While readers at different levels within the same organization might read a text, there is also the option that a text is read by readers from different fields and organizations. Naturally, this will affect your vocabulary and the amount of background information given. On a similar note, a reader with a non-technical background needs even more background information and explanation and at times you have to assume your reader has no prior knowledge of the field. The opposite case is a text written exclusively for the expert readers. Here, you should use field specific vocabulary and a fair amount of detail, but should also concentrate on providing an extensive list of references.
How can the information be presented best?
Should it be given in text format or would perhaps graphs, diagrams or even tables provide for better communication? These visual alternatives tend to communicate information faster than written text, but remember that too many visually presented details can become too much of a good thing. Likewise, given the use of visuals, how much textual support do these visuals need?