Most "bad bath" stories trace back to one thing: the dog wasn't ready, and the owner wasn't set up.
Set up first, dog second
Have shampoo open, towels within reach, and the water temperature right before your dog comes anywhere near the tub. Hunting for supplies with a soaking-wet dog escalates everything.
Pace yourself
Wet, lather, rinse — and then rinse again. Soap residue is the most common cause of post-bath itching. When you think you're done rinsing, rinse one more time.
End on a high note: a towel cuddle and a treat. Dogs remember how baths end more than how they begin.