There are a lot of ideas regarding what a bombshell is, so I figure as my starting post I will explain my definition of a bombshell.
A bombshell is a rare race, not like the average woman. You could say that she cares about her appearance; she doesn't just walk out of the house a mess without makeup. If she really is low on time, she will throw on her sunglasses to cover up her makeup free eyes(so no one sees them of course), puts on her emergency powder, and of course lipstick or lipgloss.
For example, after arriving in Paris, I was in the taxi applying my fake lashes. Impractical, you may think. But we are quite famous for our impracticality.
So you see the difference between an average woman-on-the-go, and a bombshell-on-the-go.
Looks are a priority to the bombshell. She knows that her life is unpredictable, and she doesn't want to walk out of the house a complete mess. I mean, what if she runs into her new love? Or her arch enemy? The possibilities are endless in the life of a bombshell.
Now as for how a bombshell may look, well as you know, they are quite famous for their sex appeal, and curves(hmmm, this may not be the most humble move to call myself a bombshell). Anyway, regarding hair color, well, blondes are the most common bombshells, but we do have the brunette bombshells and redheaded bombshells (they opt for a darker shade of red), as for the older bombshells, they make grey stylish.
I hope my definition makes things clearer for you, but then again us bombshells are unpredictable, so there is no definite personality. But what I stated above will give you a basic outline of our personality.