How do I improve the sound quality in Express Scribe?

There is a lot of noise/hissing/rustling on the recorded file I am transcribing. It's very hard to understand what people are saying underneath all that. I have played around with the Bass settings in Express scribe, but it doesn't seem to help. There's also quite a bit of "echoing" going on, or it sounds like they are in a big hall, rather than a small room, while talking. How can I improve this so I can actually transcribe this recording word for word?