Question about recording vocals !

Im trying to record vocals with a condenser microphone , but my mic seems to pick up every sound thats going on in the room i record in, in addition to my voice.

What are the best ways to ensure that your vocals and your vocals only are whats recorded on audacity ?

Yes, good microphones do that. Every little detail.

Record in a very quiet room.

Steve (above) is right, condensers pick up ambient sound and a quiet recording room is the answer - if you want to pick up localised sound only, use a dynamic. That’s why performers use a dynamic on stage, they only want the vocal to come through the mic - not all the drums and other instruments. Get a dynamic mic and get nice and close to it - you will just get the sounds you want…
more on dynamic vs condenser (if I may make so bold…):
http://www.cassette2cd.co.uk/studio/dynamic.htm