It can be very much frustrating if you get low marks in an assignment which you believe you have put a good amount of hard work. Anyhow, there are many ways to score high in assignments. Firstly, you should ask yourself questions regarding the difficulties in writing the assignment as well as the common errors pointed out by the tutors. Then you need to analyse these issues by dividing it into two groups, namely major and minor issues.
If you have got low or average marks for an assignment, your tutor is likely to highlight issues in your assignment like the question set has not been clearly addressed; the assignment has not been explored in depth; the assignment is not properly structured, and so on. To address the first issue, you need to read the title of the assignment carefully. Further, you can ask yourself whether the question is descriptive or analytical. However, you may also get the question as a combination of both. Here, you need to address both the approaches thoroughly while giving greater emphasis to the analytical part.
For the second issue, that is the lack of depth in the assignment, you need to have a proper understanding of the arguments which agree and disagree on a particular viewpoint. Generally, the tutors would not be satisfied with the mere repetition of the lecture material, but would expect independent viewpoint of the student. In this case, the student would have to collect matching references which support or oppose a particular idea and understand it clearly. However, in higher education, students are expected to present the argument in a neutral manner unless specified otherwise.
Finally, for addressing the third issue of badly structured assignment, you need to include one or two key sentences in each paragraph and stick to it so that you would not get deviated from the original topic.
In short, an assignment which is presented with suitable examples, good structure, and appropriate research evidence often gains good marks.