There are several high-quality web sites providing skills in palaeography (the study of old handwriting) and diplomatic (the physical make-up and contents of old documents).
You may find the following useful:
- English Handwriting 1500-1700: an online course
[Cambridge English Renaissance Electronic Service]
- Palaeography: reading old handwriting 1500 – 1800
[The National Archives, in partnership with the School of Library, Archive and Information Studies (SLAIS), University College London]
- Medieval and Early Modern Palaeography
[Dave Postles, Marc Fitch Research Fellow, University of Leicester, England.]