I find gold at garage sales, flea markets, thrift shops. Little old ladies and their beat up jewelry boxes are your best resource. It's difficult to explain precisely how to distinguish the real from the fake, so I'll just give you an itemized list of pointers.
I am willing to bend down and scrounge through boxes of junk, while other people won't bother. Willingness to make an effort is half of this.
Real gold is duller than fake. Shiny and bright yellow is likely bogus.
Look at the way it's put together. Check out items that you know are gold, and look for other items with the same kind of finish.
1/120 12K is gold filled, and has no scrap value.
If it says 925 that's silver, even if it's gold colored. It's probably vermeil.
Not all gold is hallmarked. Not all hallmarked pieces are gold. (fakery)
Buy an acid testing kit from Ebay. It's cheap and your best friend when on the hunt.
Don't ask anyone if the item is gold before you buy. Just buy it or don't buy it. Sellers' ignorance is your friend.
Real gold is heavy. Lighter pieces of the same volume are fake.
I have a packed jewelry box filled with real stuff I bought for a buck or two. Sometimes I have to clean out and just get rid of some, so my method really works.
hth
