Sony Sound Forge 9.0c Help.

Hello, lately i've been messing with musics and crap, and i want to record a song, a friend of mine told me to record the vocals with Sound Forge and then mix it with the instrumentals in some other programme. The thing is, after i record the vocals, they sound like crap with alot of background noise eventho i turned everything off. How could i make my vocals run smoother and sound better?
Im using a mic off a headset along with karaoke instrumentals. Thanks in front.