There are three things to be thinking about:
- The key message/idea you want to convey based upon the research literature
- The audience for whom you are writing
- How you will convey the arguments/ideas to your audience
The key message
It's crucial you understand as well as you possibly can the idea, the main point you want to convey. If you don't you won't be able to write about it. This means you need to go back over the literature and your notebooks. It means trying to convey the idea to someone who knows nothing about the idea1.
Will, in part be defined by the readership of the professional journal you have chosen. You can learn a lot from looking at articles that have been published in the journal. But, if you professionally identify with your audience, e.g. if you are writing for teachers of primary mathematics and you are a primary mathematics teacher then you ought to know a little about how that professional group shares ideas, makes decisions and so on.
One approach is to do a dump. Just blurt it out. Write it down. Don't worry about structure, logic, flow, just get it down. Step back and have a look at it. Have you left anything out that you wanted to include? Now the hard part is next how to shape the idea set up so you big idea is clear, the supporting and related ideas link clearly and logically to them and you try it out on a professional colleague or two.
There is more information on the notes for this task pages.