First attempts to photograph the night sky

I've been playing around for a few years with my Canon Rebel t3i. I'm hoping to upgrade the body later this year (either Rebel t7i or D80). I mostly take pictures of nature and landscapes, but this past year I had a few opportunities to attempt to take pictures of a star sky. This type of photography has a very high learning curve.

My first attempt was in Sedona, Arizona looking over one of the red rock formations from the balcony of my hotel room.
In the center is Orion and you can see the smudge of the nebula (taken with the Canon EFS 18-135mm lense at 18mm f/3.5)

My second attempt was up in the mountains on the Blue Ridge Parkway in Virginia. There wasn't too much sky due to the trees, but they provide an interesting silhouette against the stars (edit: may need to view picture full screen to see it better). Most picture attempts were about 20 seconds long.

On closer examination of the picture when I got home show that I still have alot to learn how to balance exposure time, ISO and correctly focus at infinity with my equipment. I also see how this type of photography is pushing the sensor in the t3i beyond what it can do well (issues with hot pixels). At least the process of taking these pictures is enjoyable in itself and I get to be in cool places too.

My goal is to hit a dark sky area when the Milky Way is present and try to capture that.

If people have basic tips on how to do this type of photography better, please post in the comments. I know I have just started on a long journey to learn how to take good photographs.