Actually I did almost everything wrong to photograph star trails. Normally you look for a non light polluted area, I photographed in a park in the middle of a populated area. You pick a time when there is no moon (New Moon phase) in the sky. Yesterday the moon was shining quite bright luckily it was not full moon yet. You pick a still standing subject like a rock or building, I picked a group of palm trees that were moved by the wind and still I like the image.
Enjoy and keep on working and improving your images!