The orange one (1) pretty plain. I didn't add anything to the paper, I just used three slightly different shades of orange paper, so the star looks interesting.
Similarly with the yellow (3) star, I drew squiggles with a black pen, so you'll get a hint of the three dimensional inside that way. I think it's very striking and fun.
For the pink star (4) I used both three shades of pink paper and painted the inside of the star silver, and for the blue star (5) I used more silver paint.
The last star I made was with decorative paper (6) I had and it is lovely! The paper has geometric designs, which suit the omega star design very well.