It is important to note that a 2:2 is still a perfectly respectable classification.
But, not being happy with this, you can take practical steps to improve your marks:
-Look at your assessment feedback and speak to the relevant staff member about how best to implement the suggestions.
-Speak to study skills about their essay workshops. Most institutions have these running, either via specialist staff or via the library.
-Make honest appraisals of your work in relation to the markscheme/rubric.