I am coming close to finish my first iPhone game ever, as a matter of fact also my first programming experience ever, which is a quiz game. I have all the functionality i want and is currently polishing it both from a code point of view as well as looking at the GUI.

My initial idea was not to use any specific graphics but rather focus on the game experience and simplicity and by that only using background color, orange, and white text as well as buttons. The design is based on that all ages, from learning to read, should be able to host and play this game.

However, as i am now getting close to the finish line i am starting to think what is needed from a GUI point of view.

I would like to ask for some advice what to think about when designing a GUI. Is it considered OK without any 'fancy' graphics, what is the risk without it etc.?

Also, what colors goes well together if i choose to use a simple GUI. I am thinking about color blindness etc.

In other words how do i design a good and effective GUI for a simple game as mine?

Thanks