[Acidic]

My character Diamond Song :3

[Tanetane]

Why is she so much like Rarity?
Is it because she's supposed to be related?
Not everybody is the same. Look at Sweetie Belle. The only time she's interested in fashion designing is when she wants to help Rarity out.
I've seen many copy cats of the Mane Six and others, and they're just not good characters. Not matter if they're related or not.
Too many 'shy' ponies, too many daring and dangerous Pegasi, too many DJ ponies with Vinyl Scratch's color scheme, too many bookish smart unicorns.... You get the point.
I have to admit though, not many other people copy Rarity.

Is she a background pony? If so, forgive me for criticizing her design because I've never seen her.
I'm not trying to be mean, if I've made you upset, then I'm sorry! If you want any advice creating characters you could always just PM or ask others.

[Acidic]

Rarity's special talent is finding gems, and Diamond's is sewing. The only similarity is that she's white and her eyeshadow's blue. Besides, all of my pony characters relate to a pony on the show in some way, but they always are completely different.