General purpose computer interface design techniques may be more helpful than game-specific ones. Computer interface design can be split into two parts, the aesthetics and the usability. However, it is important remember that the two are related, similar to the coloring/shading on a piece of art, and the composition/lineart.
For usability, consider things such as Fitt's Law to determine appropriate sizes for UI elements. Fitt's Law implies that objects in the corners of the screen are the easiest to hit. That only applies to mouse-based interaction though, which provides resistance on the edges of the screen.
As for aesthetics, consider basic principles of design, such as composition, and the "weight" attributed to things of different colors and shapes. Color theory will help you, as well as keeping in mind that the apparent color of an object is altered by the color of the things around it. Also consider other elements and principles of design.
When analyzing the UI of other games, take these basic elements into account. Where does your eye go first? How does it move though the interface? Understand what draws your attention and why as opposed to just copying the UI of another game.
Like others have said, design is an art, not a science. If you don't have the feel for it, perhaps it is not for you. Technical people tend to have a good sense of composition though, so not all is lost.