Try to redirect her attention with a toy, treat, something that's more interesting than the other dog, and when she looks away, praise her. If you've worked on a "Leave it" command, use that. When Tank was younger, we would be walking and he would look at another dog, I'd say "Leave it" and he would look at me instead thinking I had a treat ready for him. It works wonders.
Ravel Vom Leineholz aka Tank (9/8/2011)
"You cannot dream yourself into a character; you must hammer and forge yourself one."