Only RAW! One of the first things i did when i got my Canon Rebel. EVERY photographer needs to know this! ( I never see the point in shooting raw - learn how to shoot in light and you don't have to over edit your pics)
Rule of thirds - Center of interest; The rule of thirds is applied by aligning a subject with the guide lines and their intersection points, placing the horizon on the top or bottom line, or allowing linear features in the image to flow from section to section.