Here are some general tips to keep in mind in low light conditions:
1. use a tripod or monopod where possible and turn off vibration reduction/ image stabilization,
2. if you have to hand-hold, turn on vibration reduction, stabilize yourself (against something solid like a wall, table etc, gently squeeze shutter button at the end of your out breath) and apply the "hand-holding rule" = the shutter speed should be approximately the focal length of the lens (e.g. 100mm focal length = 1/100 of a second shutter speed),
3. shoot on manual with the widest aperture for the lens you're using,
4. use manual focus and turn off auto-focus,
5. if need be, increase ISO but keep it to a minimum to reduce noise - most cameras can handle up to ISO 800 and full-frame cameras are good up to 3200 and higher,
6. shoot in RAW because you can better recover detail in the shadows in post-production.
Suggested resources for low light photography:
"Night and Low Light Photography Workshop" by Eric Boutilier Brown at Photoworkshops.ca
Night Photography: Finding Your Way in the Dark by Lance Keimig; Focal Press, 2010 - an excellent book which thoroughly covers the topic with a clear writing style and good photographs to illustrate key points.
"Using Available Light in Dark Settings" - The New York Institute of Photography have a number of helpful short articles on many topics on their website. Here is one at http://www.nyip.edu/photo-articles/archive/using-available-light-in-dark-settings
Night and Low Light Photography, Lynda.com - it's a subscription on-line course but you can watch the introduction for free as a promotion at http://www.lynda.com/Photography-tutorials/Foundations-Photography-Night-Low-Light/90279-2.html - they have lot's of other good tutorials on photography on subscription.