How to get my DSLR camera to flash?

I have a Nikon D5000 and I have the flash on. When I have the lights dim, it'll auto flash for me, but when I have the lights on it won't flash. I understand that it's just trying to self-adjust, but I would really like that extra bit of light from the flash even with the lights on. Is there a way to make it flash no matter what the situation?

Its quite easy.

I attached the Nikon link below. Page 70 and 71 has a clear outline that shows step by step how to put the camera in flash mode.

Take it off Green Box auto and the flash will fire if it is raised. "P", Program Shift Mode, will still do all the work for you, but not lock you out of the controls like the green square setting does.

Slide the selector to M, A, S or P flash will work all the time… Don't slide it to AUTO. Make sure press that flash button located in front of the camera next to the lens. I owned a D5000 too.

The term I'm familiar with for what you want is "force flash". That means you set the camera to flash regardless of the light available. Check your owner's manual for details on proper setup.