By not shooting in auto mode. Sounds logical, but I'm being serious. Start shooting in aperture priority and do 30 minutes of searching on the web to figure out what aperture is and how changes to the aperture effect your pictures. Doing that and sticking to aperture priority will open you up to use your camera a lot more and have a lot more control over how your images look.
This should be in the beginners section. You will get a lot more help and it will be in the right place. Try using a non-preset mode when shooting and just test around.