Always Complete Your Daily and Weekly Challenges
Along with the rather generous free cards and coins that EA often hand out for logging into the app, players can also complete a number of daily and weekly objectives.
Whether it's as simple as buying an item on the Transfer Market, scoring a goal with a specific nationality player, or even using a through ball to secure an assist on goal, each of these objectives have some pretty good payouts and often have better rewards than the standard daily login offer.
Update Your Listings Every Hour
If you're serious about selling cards to make a profit, it is important that you make all of the necessary actions that are needed to earn the most profit possible.
In order to do so though, one of the best methods for selling cards is to list them for only one hour at a time. If they do not sell, simply re-list them as soon as possible.
With this method being so time-consuming, the FIFA 19 Web app definitely comes in handy, as you can make these changes without having to turn on your PS4, Xbox One, or even PC.
Don't panic though if the card doesn't sell after a few tries, simply stay persistent and you'll eventually get that profit you were after.