What Brian said would apply to a Speedlight mounted on the D7000, but if you are using the built-in flash, and the camera is in P, S, A or M mode, set the flash so the indicator on the top LCD screen is only showing the lightning bolt.
In low light, you may want to use Slow sync.
Make sure custom setting e3, Flash Control Mode, is set to TTL. (There is no TTL-BL setting for the built-in flash)
You may also find it useful to dial in -0.7 or more of flash compensation, depending on the amount of fill you need.
Check pages 144-148 of the manual for more details.