I think because many college math classes are so large, the teachers put students into groups to start out. If not, I feel like finding others students in the class that understand is the best way to learn. Like amurbach said, buddying up can make a world of difference. The other student will probably be happy to help, because a lot of times, teaching is the best way to work through problems and learn yourself. If you can explain it to someone else well enough that they understand, you surely understand.
On a different note, have your daughter ask the teacher for extra practice problems. Or if they teacher assigns odds for example, have her do the evens as well. And even though the homework may not be turned in, practice make perfect, and will definitely help improve on a letter grade. Hope this helps!