Like I've mentioned in previous polls comparing the 2 series, I only watched one season of TVD, so I can't really compare. The main similarity I know about is a love triangle between one human girl and 2 male vampires, but love triangles appear in almost all stories, and in vampire series you'd expect some in that triangle to be vampires, so that's not enough to say it was copied. Apparently there are also some character traits/story line aspects in common between the main vampire characters.

I watched one maybe two episodes of TVD. Did nothing for me and I remember almost nothing about it.