I've been trying to expand and develop my photography skills, particularly when it comes to natural subjects and landscape photos, and have come to see that taking panorama images is the next step in helping my photography to evolve. What are your tips/tricks/secrets to taking good panorama images?

Here are a few examples of my first attempts. I think these were 4 images at most. I did not realize at the time that the proper way to rotate the camera is about its lens (as opposed to my face/eyes ). As such, many of my photos have that warped sky appearance. I'd greatly appreciate some constructive criticism on these.