Camera settings: Metering is the main problem, so if you are using evaluated metering, you will need to under-expose a lot or use spot metering on your subject.
Shooting in low light conditions is tough enough, so how can we shoot in dark? Well... bring you own light.. Any light!
Use a torch or even your mobile phone to light the subject to create dramatic 'spotlight' images. Use a light source to create a silhouette of your subject.