Well, obviously you have to focus on his guilt--but it is prob best just to work through the issues which all contribute to this.
Try structuring it under sub headings, eg.
INTRO
JEWFLATS
CONCENTRATION CAMPS
TOTAL WAR and ARMAMENTS MINISTER
POSEN CONFERENCE
GUILT?
and under the headings be sure to include issues such as the holocaust etc. and of course historiography from Fest, Van der Vat, Sereny, and Speer himself.
Since it is your essay you need to write it and structure it how it suits you and your style of writing.. but i hope that helps
Oh, and once you have finished the essay be sure to delete the headings!!