Fortunately, Mardi is fairly good and I can Dremel her nails but DH does have to lay down with her and help hold her.
Archie is totally different, he hates it.
Start from step 1. As if the vet will let you visit for no reason at all, just to walk in, wait a minute, treat, praise and leave. Work up to getting on the scale. Make it a super fun party with treats and praise. Work on handling his feet, not forcing. Teaching shake might help too because it is his decision to present his paw. Don't hold it, let him rest his paw on your hand, treat, praise. Go slowly.
My vet taught me a very valuable lesson. I would come in with Archie all tense, expecting the worse. As she was trying to trim his nails, she stopped everything, looked at me and told me to breath, relax. He was reading my anxiety. We paused a few minutes, he struggled a little and then took a deep breath and relaxed and the job got done. Not saying he liked it or didn't struggle a little, but it was so much easier. I also take him to PetsMart for a trim and ask that two girls work on him on the floor. One holds him and talking him, the other doing the trimming. He's finally allowing them to Dremel his nails now.
It's a long slow process but he can learn that it's not such a horrible thing to happen. He'll probably never love it, but the job can get done.