Gold plated flatware has a thin coat of usually 14k gold. Older sets have more commodity value than newer sets (sets made after the 1950s) as they used more gold. Gold plated sterling silver has more value than items made out of an inexpensive material base. Gold plated flatware sets were popular in the 1980s and were produced in such vast quantities that they have little resale value due to the glut in the market.
To see if your particular set holds value, check out the maker's marks on the bottom of a fork. Then search for that pattern and company online to see if there is interest in it.
Gold plate is thin and soft so it is easy to mar. Do not wash in a dishwasher or use coarse materials to clean. Wash with a soft cloth, rinse, and gently wipe dry.