I am thinking of stating a news paper site what is the best way to get only unique articles and find the proper writers for the site? My site is a very niche site.
Write them yourself. Or pay a respected article writer to do it - and I don't mean those "$5 for a 1000 word article" style, unless you like your English language written in Swahili Perhaps try users of a forum to which your niche belongs?
"what is the best way to get only unique articles and find the proper writers for the site" I suggest you hire writers at freelance sites. There you will find excellent writers who will deliver unique content.