I started out with a corded dremel, but I liked it so much I bought a cordless dremel, a model 8200 with a Li-Ion battery. From what I understand (never having used one),the pedipaws and other cheap battery powered ones just don't have the power.
With my 8200 I do as BearMurphy said, except I don't hold it for more than 3 seconds. I have it going fairly quickly (about 10,000 rpms) because you need to let the tool do the work and NOT press! Even 10, 000 rpm's is maybe 2 on the setting scale from 1-10.
I thought a nail guard would be useful but quite honestly, if you look at what you're doing and let the tool do the work, it's not needed.
Here's what I did, NOTE: This was spread over several weeks, it's not like I did each step one day then the next day moved on. Also, as Bear said, " it can be a slow process to train your dog to accept it but once you do it's worth it in my opinion"
-I put the tool on the couch, but not right next to Teaghan, and left the room. I let her explore it.
-I fed her treats off the tool
-I touched the tool to *one* toenail, but the tool wasn't running
-I turned the tool on briefly in the same room
Again, the steps were over a 2 week period.
Pretty much each time I did a step, I gave her plenty of treats. The goal being that when she sees me with the dremel, she knows that wonderful things will happen!