Some people find it helpful to plan their work before they begin writing. Starting writing with a structure in place can help keep your writing focused and prevent writer's block. Others find it more useful to get started and see what structure emerges as they write.
Either way, your piece of work needs to have a logical order that makes sense. This allows the reader to follow your train of thought and understand the points you are making. If you are struggling to put your thoughts into a logical order, try talking to someone else about what you are going to write. Ask them to note down the key points that you make so you can look back and use this as the basis of your plan.
Each paragraph should follow on from the one before it and lead into the one after it. If a paragraph does not relate to the ones immediately before and after it then you may want to consider moving it, or making the links clear. There's more information about structuring a paragraph on the next part of this guide.
If you are writing an essay, or making an argument, it is a good idea to include an introduction and a conclusion. We recommend that you write the main part of your essay first, then the conclusion, and leave the introduction until last. This might feel strange, but it is much easier to write an introduction once you know what your work is going to say. The introduction sets out the points that you are going to make or the case that you are going to argue. The conclusion summarises what you have written - you shouldn't include any new information here.