I haven't skilled up parrying yet. I have skilled up shield, and I'll offer what I have learned from shield skillups. Whether it transfers over for parrying, I don't know - I hope some of it does.
First: Shield Torque did help me with shield skillups.
Second: For skillups of defensive skills, I wanted to find mobs that used physical attacks, hit a lot, but hit for low damage, and that didn't throw a lot of effects at me that I didn't want or couldn't handle. Eva Down is actually your friend for defensive skillups. Best mob families based on these criteria are:
Chigoe Family (Best)
Mandagora Family
Bee Family
Beetle Family
Crab Family
The Chigoes in Caedreva Mire actually worked only to about 190 for me, but my Shield capped at 210. There are other Chigoes in Aedwa Subterrine (or however your spell it). I had capped Shield by then so didn't try them, but I know they are higher level than the ones in the Mire. Be close to a zone if you try these though, they link quite readily.
For Mandy types, Pucks in Den of Rancor work pretty well, but they're dangerous. Korrigans in Tree near Cloister of Storms work pretty good too, but they are a lower level.
A third major thing i learned may be important. Regardless of whether a skill is A, B, C or whatever, when you are getting close to capping it at 75, the same considerations seem to always apply. You'll need to be fighting T mobs for the last 5 or so levels, and either soloing Pucks in the Den or getting what you can from merit parties to get the last 10 levels. Prior to that, for C-20 (Cap level minus 20) to C-10, Korrigans in Tree or the Steelshell in the tunnel to Cloister of Storms.
Only other thing I can think of is - to skill up shield skill, a light buckler-type shield is best. Perhaps for parrying a couple of daggers that hit for low damage but that are "fast" might be best.
Again, I don't know if any of this is useful. I hope it is.
Fire