i cut Lola's nails about twice a month with a normal guillotine cutter, try to get her when she's out of the tub when her nails are a bit softer. Her back toes are black. I usually cut where the new growth is, like a hangover. Then I cut very thin slices until I see more flesh than nail. I think I should cut more, but it's mostly flesh by the time I stop. Then Lola loves to get her nails filed with an emory board.
I taught her how to like it with LOTS of treats. Now if the treats are handy I will give her some throughout, but if not, she still tolerates it. She's 4 yrs old now.