Are you fishing around a lot of rock or brushpiles? Typically when I see a lot of fraying in a braided line, its due to abrasion - that is to say the line is rubbing against something hard/sharp. If that's the case, moving to fluorocarbon line would be smart. If you're going to replace the whole line, I would recommend Tatsu by Seaguar. If you think the line could be salvaged, tying on a fluorocarbon leader may help reduce fraying of the braid. For just a leader, you can usually get away with cheaper fluorocarbon and I've had good luck with trilene 100% fluorocarbon.