- Get the white balance right. It matters. Canon auto-white-balance is very cool in my opinion. If you set white balance to 'sunny' on sunny days, 'cloudy' on cloudy days and 'shade' when you're in the shade -- you'll be amazed by the difference. It sounds so obvious, but very few beginner photographers do it. (If you're shooting RAW, you can try different white balances when you process the image.)
- Do use exposure compensation (EC). The camera meter is not that smart. It likes to make everything 'pretty bright'. If for example, you are taking photographs in dark woods, the meter will make the scene much brighter than it is. Use negative EC of -1/3 to -1 to have the image captured match what is before your eyes. Likewise, when you find your images look to dark, use EC +1/3 to +2/3 to make them brighter. You are much smarter than the camera exposure meter, you need to constantly be reviewing images on the camera LCD and adjusting EC as needed.
- If you shoot any portraits, get a prime lens (like the EF 50 f1.8,EF 50 f1.4, EF-s 60 f2.8 Macro, 85 f1.8, EF 100 f2, EF 100 f2.8 Macro) and take some portraits at wide apertures. Even if it's only the Canon 50 f1.8 for $85 -- you'll be amazed at the differences in portrait photographs this lens produces vs. the 18-55 kits lens. SIDEBAR: All these lenses (except the 60 f2.8 and 100 f2.8) need to be 'stopped-down' a little for them for them to be sharp (around f2.5 of so). These prime lenses are extremely sharp, small, light, have really wide apertures, are great for low-light photography, and cheap (you can buy 2-3 of these lenses for the price of one 17-55 f2.8 zoom). The 2 Macro lenses are especially nice because you can use them for both portrait and Macro work. FYI: The 85mm-100mm focal lengths on an APS-c body (XTi, XSi, 40D, etc.) is too long for most indoor use, but are great for outdoor shooting. Go to Fred Miranda's site for end-user reviews of these Canon prime lenses.
- Know the basics of photography and how to use your camera (in detail). This includes shooting modes (P, Av, Tv, M), shutter-speed, aperture, ISO, depth-of-field and how all of these relate. Read the book referenced here (or something similar) and read your manual. Here's a good Canon educational website also.
These are 4 'biggies' in my mind. Doing all 4 should really take your photography to the 'next level.' If you're already doing some or all of these, great.
Oh, yeah #5, subscribe to this blog :)