Here, off the top of my head, and in no particular order, are a few of my key tips for new photographers.
1. Always shoot RAW.
2. Back up anything you want to keep in at least two separate locations.
3. Don't worry about getting the best camera and other gear when starting out. Work on technique.
4. Learn your camera's ins and outs.
5. Practice shooting anything and everything.
6. Experiment. Try things you wouldn't normally shoot. Look for new angles and options. When you're about to shoot something, turn around and look in the other direction too.
7. Take into account what others think of your work, but only to a limited degree.
8. Don't obssess over sharpness. One of my favorite catchlines: "Artists don't pixel-peep".
9. Know all the rules of composition -- and break them regularly.
10. Take advantage of the golden light at sunrise and sunset, but don't let yourself get locked into shooting at only these times.
11. Use a tripod when it is necessary. Don't use it when there's enough light to make it unnecessary, if it will slow you down or impede your creativity.
12. Resist the temptation to overprocess your image with gaudy oversaturation or cheesy effects. These will appeal to you when you're new, and you'll cringe at them later on. Trust me.
13. Don't be afraid to bump up the ISO if necessary. Modern cameras make very clean images even at 4-digit ISOs.
14. When you're ready to spend money on equipment, spend it on good glass first, not bodies. Glass retains its value; bodies depreciate almost as quickly as computers.
15. Get a decent photo editing package and learn how to use it. You don't need full Photoshop to start.
16. Learn how to read and understand histograms. They are THE key tool to checking if you've nailed exposure.
That's all I got right now. :)