These cards can fluctuate dramatically in FIFA 23 Coins value based on the performance of the team and player - and , this year, presumably, based on the country's performance, too. You can see this on the price graphs that are available on FUT comparison websites, where stars strikers will increase in price prior to an event, but then rocket after scoring, or drop in a flash when the team is in the back.
The most effective method to earn money from the cards is to generally purchase them during neutral periods to hold them for a while, and then sell them in the hype. For instance it is the case with Liverpool's Darwin Nunez has had a slow start as a player on Merseyside with two goals from the league during his seven initial matches.
After the disappointing 3-3 draw with Brighton and with tough fixtures to come The OTW price - three days since his release is at or around 70k coins. If a shrewd speculator chooses this time of low prices to buy one, and then consider selling it before the Liverpool's next game takes off, especially when Nunez is on the team. A riskier investor could even keep it in the game hoping Nunez scores, but the risk is higher.
One thing to look out to look out for with OTW cards is that the upgrades have already been 'priced'. We all know that Man City are going to beat 3/8 games to gain Haaland their first OTW upgrade, as an example which is one of the reason for the exorbitant price in-game.
Don't be deceived by players who are likely to win those three wins with the hope that prices will rise when the time actually comes around. In all likelihood, that will just result in lots of individuals trying to profit while simultaneously which could drive the price down.
Ultimately, Ones to Watch cards are predictable in a few ways, but they are also unpredictable in other. Their unpredictable nature is what makes them interesting, but being aware of those predictable peaks bottoms, buying when they're buy FUT 23 Coins down, trading in the midst of hype - is how you will be able to earn coins from these cards.