Believe me, I'm not into spending cash just to say I spent 
cash.  That means I don't buy equipment that doesn't 
return the investment to me.  So this tip is a suggestion 
to spend what some people call "real money."

Your camera needs a firm foundation to shoot great shots 
in low lighting.  I'm refering to your TRIPOD.  It will 
be worth it to invest a few hundred dollars in a good 
solid tripod for low light shooting.  Unfortunately, 
flimsy tripods just don't do you any good.

The smaller and lighter the tripod, the less stable it 
will be for shooting.  This includes those "hi-tech 
carbon fiber" tripods.  If you're planning on doing a lot 
of night photography with shutter speeds longer than a few 
seconds, it's better to pay for and carry the extra weight 
of a sturdier tripod.  

If you do buy an expensive tripod, you'll want to make 
sure it has a few professional features while you're at 
it.  For instance, you want to make sure it has a way to 
hang a weight bag from the center column.  This helps to 
stabilize the tripod even more and is valuable in windy 
conditions.  

While I'm on the topic, you might also invest in a remote 
shutter release or learn how to use the self-timer on your 
camera to minimize camera shake due to your hand being on 
the camera.  A remote trigger (and the self-timer) allow you 
to fire the shutter without having to touch the camera 
body.  This makes for cleaner shooting without shake. 

Also, make sure your tripod has a quick release plate.  
This plate attaches to the bottom of your camera and allows
you to take the camera on and off of the tripod with a 
simple lever (rather than having to unscrew it each time).  

There are two parts to a tripod:  the tripod head, and the 
tripod legs.  You can buy these separately, but most will 
come paired already.  A couple of great camera/gear stores 
I recommend are B&H Photo/Video, and Adorama.  If you 
peruse their websites, you'll be able to get a good idea 
of the variety of tripods that are available, and compare 
their features.  

There is a ton of info on the internet about tripods - 
just do a search for "still camera tripods" and you'll 
learn more than you wanted to know about tripods.  

The main take away from this tip is: DON'T buy a $15 
tripod.  Your new DSLR deserves a better, more stable 
future...