If you're doing AQA History B (which it looks like you are from your question, which is what I'm doing too), then the structure is as follows.
Describe questions - 4 marks.
Spend about 7 minutes on them and write about 2 specific points in detail.
Source questions - 6 marks.
Spend about 10.5 minutes on them and the structure is: NOP (nature, origin and purpose of the source), (why you) agree, (why you) disagree and conclusion.
X or Y questions - 10 marks.
Spend about 17.5 minutes on them and the structure is: Intro (briefly re-instate the question, describe and explain the first factor in detail, describe and explain the second factor in detail and then conclusion.