1 Structure
Be sure that your paper has a clear structure and storyline to answer the research question. A good rule-of-thumb is that you are able to summarize the main points in about three sentences. These main points should usually tell the reader why he/she should read the text (introduction/motivation), what are the key insights from it (facts), and what follows from these insights (conclusion).
2 Be clear
You write to be understood, so be as clear as possible. This means a clear structure for the entire text (see Principle 1), but also for individual paragraphs and sentences. It is usually good to use graphs and diagrams to illustrate, but do not do this excessively. Also, it is usually very helpful to give your text to someone who does not know the topic you are writing about well. If this person asks lots of questions, you should re-write.
3 Be simple
While some scientific terminology is usually needed, use plain and easy-to-understand language. Follow George Orwell’s rules of writing: If it is possible to cut a word out, always cut it out; never use a foreign phrase, a scientific word or a jargon word if you can think of an everyday English equivalent.
4 Be precise
Define the key concepts you use, but do so as briefly as possible. Clearly state whether evidence you cite is causal or descriptive. Make sure that it is clear where your conclusions come from. Avoid general statements that do not provide information (“This is an interesting topic”). Cite your sources.
5 Write – and re-write
Many people struggle especially with the first draft. The solution is simple: Just write down what you have at that point, ideally with a clear structure. Then go over the text again several times, bearing in mind Rules 2-4. But you do not want to go as far as Haruki Murakami in his book “Novelist as a profession”: He usually recognises that a text is done when he puts back commas into the text that he has deleted previously. Being able to finalise a text is a virtue, so do not lose sight of this.