Focus your narrative
It can be helpful to think of your article as a story, and – given the length of a typical journal article – a focused narrative is crucial. Resist the temptation to share the breadth of your understanding of a subject, or communicate the sophistication of an extended argument from a dissertation chapter. That's what the book is for!
Rather, be focused and selective in choosing what’s essential to the story you want to tell, and use foot/endnotes to tease that your article is part of a larger study. To return to the literary metaphor, you don’t want to present a synopsis of a novel, but a short story that sketches a vivid, evocative portrait of a particular moment in a character’s life, one that reveals enough context to establish the narrative’s significance without distracting from its centrality.
Be sure that your narrative starts...well...at the start. It’s difficult to overstate the importance of an effective first paragraph. Leading off with a summary of the previous scholarship can be disconcerting for those unfamiliar with the field, and boring for those already in the know. Similarly, resist the temptation to start with a lengthy anecdote or description of a particular historical moment, however vivid or evocative such a tale may be. Even if the illustration is valuable in the overall course of your argument, that significance will only become apparent after the reader invests enough time to actually reach the argument itself, and it's important to let your audience know what your piece is about right from the start. Not only can it help your work stand out in the eyes of an editor combing through submissions, it can (eventually) hook a reader flipping through the latest issue of a journal and deciding what’s worth reading first (or at all).