I'm currently doing my coursework for A Level - I'm quite worried about it as my friend who loves History and was predicted an A overall got a D on her coursework, whereas people who were predicted D's overall got an A on their coursework! Apparently you just have to be really explicit. Don't ramble, get to the point. After each paragraph, link back to the question so you stay focused and, for the sources paper, cross reference sources to develop your argument!
I agree with Elle J, once you've got the structure sorted, you're off to a good start! For my AS, I hadn't a clue about what the sources paper was saying but I still came out with an A because I just stuck to my usual structure!