Lighting / Photography / Sunset?

How would you light up your subject without too much brightness on their face with a sunset behind them? The sunset always comes out beautifully however my subject is slightly too dark. I have a Nikon D7000 with the attached flash.

Turn up the flash power or use a reflector.

http://www.altitudestock.com/image/I0000grzJzF_abc4

By attached flash do you mean the built in flash or an off-camera flash? You will need the latter with a diffuser. I would personally use an off-camera flash with -1 stops flash exposure compensation being set off wirelessly about 90 degree from the camera. As for the exposure metering, i would use the sunset in the background for that. If you can, use a golden filter on your flash.basically you need to try out different settings and set ups till you get what you want, but this is the general idea.best of luck.

Http://www.adorama.com/alc/article/Outdoor-Speedlight-Portraits-AdoramaTV

If your subject is just slightly too dark you may want to try to increase the exposure.
Using flash would help too.

Attatched flash…
you can get a cheap external flash for like 50 dollars.

Force the flash. What we call a "fill flash."

I'm not familiar with your camera, but it should have an override feature that allows you to activate the built in flash, even if the camera's metering tell it there's already enough light coming in from the sunset.

Use a reflector, or selectively adjust the exposure on the subject in post processing.

If you only have the built in flash, then use a bit of fill flash. Meter & expose for the sky (or even underexpose it by a stop or so to get rich colour), then pop a little flash onto the subjects face. This will however be hard, frontal light.

Better still get an off camera flash - you can then have more directionality to the light and you can modify it to make it softer and a warmer colour temp (gel it with a 1/2 or 1/4 cut CTO gel).
Example of mine;