floor pans repair

I just gutted the interior of my 64' valiant, and the front pans have rust pin holes and the rear pans have massive rust holes. I know I need to cut and patch, but is there anything special I need to be aware off when I am doing this? Its my first time and I want to do it right! O:)
Try to find the spotwelds and drill what you can,when replacing new metal,you can drill and weld up.This will help keep your patches connected to your cars frame structure.Good luck.