I respectfully disagree with the above comment about not using the automatic setting. I use it on my Canon 40D all the time. Those settings all have something to offer. Find out what that something is.
Using automatic white balance, though, is another issue entirely. There's a site called Earthbound Light that is really helpful. One of the owner's best posts deals with white balance, and ways to warm your images up or cool them off. You will find it here:
The Zen of White Balance - Photo Tips @ Earthbound Light
Also, consider the camera's visual focus points inside the viewfinder. I select these manually to tell the camera not only where to focus, but where to throw the light from the strobe. In other words, I will turn most of them off and select, say, the top center one, or maybe the one on the far right or left, if that's where I want the focus, the light, or both.
These things are fabulous tools, more computers with lenses than mere cameras. I think the most basic tip is to carry your camera's manual in your camera bag. Get to know it really well and don't be afraid to pull it out to look something up.
Good luck and good pictures!@