White balance essentially adjusts the color of your picture for the type of light you're dealing with.
If you hold a pice of paper up in orangey candle light, your brain adjusts and makes it look white. In greenish florescent light your brain will do the same thing. The camera can do that too, but you may need to help it a little. Enter white balance.
You have three options with white balance.
1. Have your camera auto white balance
2. Manually adjust the white balance settings
3. Adjust your white balance with editing software
For my camera, auto adjustment is usually fine (with a little touch up afterwards), but knowledge is power! Here is how manual pre-set white balance adjustments can change your picture:
Cloudy Tungsten Light
White Fluorescent Light Flash .
Clearly, the camera interprets color a little differently with the different settings. For the corner of my room, I liked the Daylight or White Fluorescent Light settings best (depending on my mood).
Let's say you're taking a picture of your bathroom or kitchen. There might not be any natural light, so you have to turn on those tungsten or florescent bulbs... Not usually a nice picture, but a little white balance could make a huge difference.
I have two bathrooms in my apartment - one for the toilet and one for the shower. I know it's strange, but I can't get off topic ranting about it so I'll just point out that (also) oddly, they use different types of light.
Both Rooms with the Daylight White Balance
White Fluorescent Light for one and Tungsten Light for the other
Now I'm not saying I love the light in either, but do you see how much more even they are? They at least look like they're from the same apartment!
Another option is custom White Balance adjustments using a grey card. I don't have one and I'm more interested in investing in a tripod at the moment, but you can learn more about that option here.
UPDATE: Stefani from Dreams of Nyssa (31 Days of Clouds - so happy!!) offered a great tip for custom white balance without buying a grey card in the comments of this post. Instead, just use a white piece of paper! She's even used a kleenex in a pinch :)
With a few more tools we'll conquer those dark inside rooms yet!