All of the guys above are suggesting you can take measures to assure your anonymity, but no-one gave you a solid advice. There are certain sites, mixers that provide you a highly secure service. They scramble your coins with their own and prevent others from tracking your BTC.

Let's say you receive ten $100 bills that have consecutive serial numbers. Someone could check where those particular notes end up and figure out what you used them for. But you could go to a bank and get ten different bills that are basically untraceable.

You could try any, but I highly recommend Bitmixer the site in my signature bellow.