I always get asked by people new to SLR cameras for advice on what to do, and my advice is always the same and I shall share it here.
1. When you first get the camera, leave it on automatic! Don't touch all those fancy buttons, just leave them alone. I'm serious about that too, photography is more about finding the right thing to shoot as opposed to the proper technical settings. If you feel like you absolutely must play with settings, then go with white balance. No, I don't mean take pictures using the manual kelvin scale, way too complicated. If it's bright and sunny out, set your white balance to the little sun, if it's cloudy then the cloud setting, and so on. Really I mean this, just get used to looking through the lens and how angles can change everything. Stay in automatic for bare minimum 6 months, and I mean six months of heavy shooting. If you don't shoot that often, then a year or more.
2. Once you are ready to play with settings more, you want to go to "A" or "S" modes. My first step into the non full auto mode was in "S" mode because I was taking waterfall pictures a lot back then, however I expect most photogs to go to the "A" mode. They stand for Aperture priority and Shutter priority. Aperture is depth of field, so when you see a photo where only the subject is in focus, they used aperture to attain that effect. What you need to know for aperture is that the smaller the number on your camera, the smaller the depth of field (when you read articles and they talk about using a large aperture setting they actually mean a small number. I understand that this scientifically correct, but it's confusing and stupid if you ask me.). So when you use the aperture setting you choose how much of the photo you want to be in focus and the camera choose the shutter speed to go along with that choice, it's semi-automatic. So I am taking you up in steps. Shutter priority, does the same thing as Aperture priority, its just that in shutter you select the shutter speed and the camera selects the aperture. Shutter speed comes into play for night photos, blurring effects in photos (such as the water falling in a waterfall), etc. Now you are paying attention to the angles of your shot, and one setting on your camera (two if you are playing around with white balance).
3. Finally you will think you are ready, and you can throw that camera in to "M" mode, which is the much revered Manual mode. Full manual, there is no help with this one, and there is no faster way to screw up your pictures! There is also no better way to have full control over your photo either. Manual mode requires a lot of thought for each photo and you should always think about what you want the photo to look like and then try to achieve it. Just remember that these days you have it easier. You can look at the camera's viewfinder and tell immediately if you got it right or not. Film days were terrible, you took a picture and hope you had things like you wanted.
So that's my advice to newbies. Take it slow and in steps. If you try to take on too much at the beginning, it will overwhelm you and you won't have fun. If you don't have fun, you won't continue working at it.