Many more long walks on concrete will help.
Practice paw handling. If you can get a little acceptance, you can try using an emery board lightly, one nail at a time.
Consult your veterinary practice’s technicians. These nurses want to help your dog become a good patient.
We rarely use nail clippers on dogs at my practice. The dogs do much better when we grind the nails with a Dremel… that takes practice to do well. Similar retail items (like the advertised Pedi-Paws) at the $20 price point are severely underpowered.