Ray, the German immigrant that started Deer Search Inc above worked with the NAVHDA (North American Versatile Hunting Dog Assoc) and I have met him and read his training manual. I have also trained Drathaars (German Wirehaid Pointer) to do this work. Here are a few things I learned.
Training yourself (the handler) is almost as important as training the dog. You must learn to "read" the dog on trail, to know when he is on track and when he has lost it.
ALWAYS use a special collar and lead when training and working blood trails. A wide collar or harness and 30 m lead is traditional. This teaches the dog that when this collar and lead is on there is blood to work. Never use this rig for taking walks or anything else.
Start with trails you have set and marked with scraps of paper. Make them short and lots of praise for success. Some dogs like treats at the end.
Eventually you can make the trails longer, older and even have others set the trails so you do not know where they go.
Blood is blood. You can use beef blood from the local locker, have them save you some. There are directions in training texts on how to keep it.
Work your dog on any blood trail you or friends have even though you have already found the deer. And make yourself and dog available to other hunters to help find their deer.
Good luck and good hunting.