Some links to stuff on learning journals
This is a really simple and practical guide to learning journals
http://www.worcester.ac.uk/studyskills/documents/learningjournals.pdf
This is a more academic approach to learning journals, that might help you develop an understanding of the theory behind learning or reflective journals
http://faculty.rcoe.appstate.edu/koppenhaverd/f06/5040/read/thorpe04.pdf
Some more practical information