One trick I used to use, especially in terms of turning my endless notes into essays (although this isn't so useful in exams) was to do a little numbered 'mind map' thing so 1) intro to include blah blah then 2) First point blah

I would then go through all my notes and research and number bits accordingly and also asterix the particular bits which would link the sections together (as this IMO is where essays can often fall down, when they seem dis-jointed and have no flow).

Then when I came to write the essay it was easy to translate my notes and research and link all my thoughts into a 'journey' for the reader.

I would use a simplified version of it in exams, as obv had no notes. However, most of my history and English A-levels and English degree was course work anyway.

Hope that makes a bit of sense.