* Built in Flash = Badness. Never use this. But if you really must, put a white piece of paper in front to diffuse the flash.
* 50mm f/1.8 or better. It's a must!
* DoF Preview. Use this feature!
* Get optical filters for all your lenses (keep the lens front element from scratching, UV doesn't really make a difference in Digital), specially when travelling and outside. Remove this for night shots (internal reflections more visible due to many point lights).
* Circular Polarizers, they do wonders for sky, water, or various reflections from subject/items.
* Use center AF only and get used to aiming at subject, AF hold, and shoot. Kind of painful, but less painful than having the camera guess the wrong AF point for a great moment.
* Auto (Bad), Tv (Sports, Action, Fast things), Av (still, portraits), Program (Keep on this by default).
* Join a photography forum or community and post photos to be critiqued and people to give you feedback.