Check out this great post from Lace & Lacquers. She uses decals from three different sheets including flower decals, Valentine's decals, and star decals. I think they all look great. Don't you?
Quotable (a good tip for application):
"I'm becoming better at applying these decals. The first time around I wasn't too big of a fan because I would get little folds sticking up. I've learned that while the top coat is still wet, I can take the top coat brush and smooth down the parts sticking up for a flawless look. Live and learn right?!"