Introductions are probably one of the hardest things to construct at first when starting the history.
People make the mistake of having a long paragraph for an introduction, where it just needs to be about 3 lines showing your clear judgement.
So for example,
''The foreign policy of Henry VIII failed to achieve its objectives in the years 1509 to 1547.''
Henry VIII had a series of different aims for his foreign policy such as breaking from Rome which he achieved but ultimately he failed to achieve the majority of objectives during these years, for instance ...... (then give an example of whether you said it was a success/failure etc)