I need to improve my controlled assessment, which is about the extent of Nelson Mandela's contribution to the end of South-African Apartheid

Hi, well lucky you, because that is excactly what I wrote mine on. 

In terms of structure, begin with an introduction, then present each side for and against, and lastly, a conclusion.

Use PEE(Point, Evidence, Example) for each point, and remember there is no such thing as too much evidence! As long as it's relevant, it's fine.

Use extracts from his autobiography and his website. There are numerous documentaries about him too. Hand in drafts to your teacher to check before final editind and submissions, and if you email it to me, I can check through it too.