Peer-reviewed research article vs. dissertation
You're writing your dissertation and want to publish your first research article. What is the difference between your dissertation and a publishable article? Working at a peer-reviewed journal, I have seen manuscripts of all types including those that look like they were copied and pasted from a dissertation. Research articles are concise summaries of your work directed at readers who are experienced in your area of research. Dissertations serve as a platform for an evaluation of your expertise and work. If you keep this in mind, then you will have a much better chance of having your work published.
How to write a great paper for publication
First, let's review four sections of any research paper: introduction, results, discussion, and methods. I have not included the abstract, as this requires an entire blog on its own. Second, I will give you a strategy to develop your paper that will put you on a path for success.
Roles of a dissertation include demonstrating an in-depth knowledge of your field, assessing your ability to define a problem, creating a hypothesis, and designing an appropriate tool to test it. When you are writing a paper for publication, all of these are already assumed. The readers are experts and not on your committee. Your introduction should include a few points to orient the reader as to what is known, what you are aiming to determine, and how. The last sentence of your introduction should state that the objective of this research is to determine whatever you are interested in by using your chosen tool.
The results that are discussed in your research paper need to be restricted to those that are relevant to answering your objective. No matter how interesting a particular experiment may have been, if it isn't directly related to your research question/objective, it will detract and ultimately sabotage your efforts to have your work published. It will prompt reviewers to question the structure of the research plan and lose focus on the objective. They may even envisage a different paper centered on a new objective. Keep it simple.
The discussion section must not repeat the results. If you repeat the results, then you have consumed your word count unnecessarily and bored your readers. The discussion is the opportunity to address your objective. The discussion should take in account your data, as well as data from supporting studies. It must elevate the work so it can be applied by other researchers. A discussion should include the most relevant limitations of your work and provide an intelligent conclusion.
Materials and methods section
The methods section must include the sufficient detail for someone experienced in your area to replicate your study. It must be concise and should reference previous work, so you don't have to repeat details. The steps for performing a routine experiment don't need to repeated, it is adequate to say what was done in a general way with any unusual details expressed explicitly.
Choose your journal and manuscript type carefully
An author must know the audience. In the case of writing a research paper, you must know where the article will be submitted before you start writing. It is imperative that you go to the website of your chosen journal and read the instructions to authors. Ideally, templates will be provided so your document will be correctly formatted. Be sure to correctly choose the type of manuscript you are intending to write (e.g., original research, review, etc) and verify the word count. These two factors will have a tremendous impact on your manuscript and need to be carefully considered. You may want to switch journals at this point, if it isn't what you were expecting. I have returned manuscripts to authors without review, because the author failed to submit the article in the correct format or has exceeded the word count. If an article does proceed in the wrong format or with an elevated word count, then it may fail at a later stage simply because the senior editors and reviewers are distracted by the flaws in the manuscript preparation. If you didn't care to format it properly, then the reviewers are wondering what else is missing.
A practical strategy
With the correct journal, article type, and word count in mind, you should start by writing the results section. Considering the study objective, prepare tables or figures and/or write the results in a concise manner to support the objective, and in parallel, write the methods. Only include the necessary experiments and details. This preparation will logically lead you to write a discussion of the results (not a repeat of the results), limitations, and enlightening conclusion. After reviewing what you have written (results, methods, and discussion), you will see that there are a few sentences required to orient the reader (i.e., someone with expertise in your area) in the introduction. Write the introduction, which will end with your objective statement(s).
Edit for grammar and style
Now that you have prepared first research paper, have it properly edited for grammar and style. Send the instructions to authors with your manuscript when having it edited. When a paper is written poorly, the editors and reviewers are distracted from the content. A good research paper can be rejected, because its message is lost in cumbersome language.