Definition:

fussy about small details; fastidious

Example:

"I have seen the most reluctant and persnickety buyers change before my eyes when they at last encounter the Perfect House. It's downright touching." – Felicia Stidham, TheGeorgetownDish.com, February 13, 2011

About the word:

Persnickety is an alteration of the older (and more insulting) pernickety, which may itself be an alteration of particular.