These are a few of the things that have made me a better photographer. I hope that you can benefit from my experience.

Tripods:
No matter how steady you can hold your camera, you're going to run into a situation where you can't use a flash and can't use a shutter speed faster than half the length of your lens. That means you're going to have a blurry picture. I know, tripods are big, heavy and cumbersome. That doesn't mean you can't take one with you everywhere you go.

When I'm out on a shoot, I always have at least one tripod with me. For some work, I have an older, heavier aluminum tripod, but that's too heavy to carry out into the tundra. One of the newer carbon-fiber tripods will serve you well because it's light, sturdy and has a hook to hang your gear-bag on to keep it from flopping over in the wind.
Film:
Why use film? Because it's cheap and extremely high-quality. Film has been around for about 100 years and has been getting better since it was first developed. If you want the best image possible, use film. It has it's drawbacks, but they're nothing that a light meter and checking your exposure with a digital camera can't overcome.
RAW Files:
There are many arguments against using RAW files. "They're big", "it just adds to your post processing effort" and "who needs all that data anyway". Well, I do, and so do you. RAW files contain all the data captured by the camera when you took the picture and they don't have loss due to compression. That means that you have much more freedom for editing after the fact and a much higher quality image. Besides, storage is cheap these days. But don't take my word for it, Wired has a great writeup on this.
Manual Mode:
Most people use one of the many automatic modes on their camera and many cameras, especially the little point-and-shoot ones only have those cryptic icons to indicate mode. Even if you have memorized the manual and do know what the icon of a mountain with fireworks behind it means, those settings were created in a lab for average conditions and, as a result, will take average photos. Learning a few basic things about how to use manual mode will improve your photos immensely.