I never actually went into this club because the line to get in was absolutely insane. I went with a group of about 10 or 12, and then me and my roommates decided to leave after waiting for an hour and half (and after a bouncer told us that we didn't really want to go to Fabric) and went to Ministry of Sound. However, from what my friends who decided to stay told me, it was not that great. This club is apparently notorious for its drug-paraphernalia usage. If this is your scene, then it's all good, but if you want good, clean fun, it's not. Everyone was high according to one friend, and the music was horrible according to another. So use your discretion.
Take the Circle Line to Farringdon. Make a left out of the tube station and follow the road.