Must be online to complete this achievement.
Choose Ultimate Team from the main menu.
Your "starter set" you are given initially are not tradeable. Additionally, there are certain cards that can only be traded for each other (certain tiers cannot be traded for other tiers). You also cannot trade cards that put you underneath the minimum number of cards required for that type (you must always have 1 stadium, 1 QB, etc.).
You can get this achievement for trading anything: Jersey for Stadium, Coach for Contract Extension, Player for Player, whatever.
To make a trade (choose either option 1 or option 2):
1. Scroll down on the MUT menu on the right to TRADES. "Search Trades" (sort however you'd like), find a card you want to trade for and submit an offer through there. At that point it is up to the person that posted the original card to decide if it is accepted or rejected. You will be notified when a decision is made under COMMUNITY on the MUT menu in the "Recent News" area. You can also track the status of all trade offers under the TRADES portion of the MUT menu.
2. Scroll down on the MUT menu on the right to MY ULTIMATE TEAM. Open "My Cards" and scroll through to find the card you want to trade. Click "A" on the card you want to trade and scroll down to the next to last option "Add To Trade Block". It will then prompt you for your requirements [if you are trying to do this quick and easy just leave the default options so you get all kinds of offers]. You will be notified when an offer is made under COMMUNITY on the MUT menu in the "Recent News" area. You will then have to approve the trade by scrolling down to the TRADES portion of the MUT menu and open the "My Trade Block" and select the card that has the offer(s). (Note: If the card does not have the option to add to trade block then it is either a Starter Set, Demo, or Reward card. These cannot be traded or auctioned).
Once a trade is accepted the achievement should pop. *Please note, I have a friend that made multiple trades and the achievement didn't pop. If this happens to you RESTART your Xbox and the game. You will have to do ANOTHER trade, but it should then unlock.
Good luck everyone. Have fun!