My pup hated getting her feet wet, too. She's still too small for boots, so when she crawled onto my feet, I would gently place her back in the grass. After a few days of doing that, she seemed fine. But I always go back in and towel her off after she's been in the wet.
I think you just have to be encouraging and use praise when she's in scary situations. Does she play with small toys? Can you increase the size of the toys she uses so that "big" things don't scare her?
Roxy is a little firecracker, so I'm not sure any of this will help, but it's worth a shot.
