This may sound funny or even a bit silly, but I trained my parry to GM w/o blade spirits or by fighting monsters. I went to Brit/Tram in the sewers and had about 6-7 sewer rats attack me with only a small shield. Trained to GM in about a couple hours. Keep in mind you will need to heal, even though they only hit for 1hp. I used Chiv to heal, as it was my highest healing skill.