McCarthy scored just once in seven appearances for the Irish U21s and has yet to score in his eight games for the Irish senior team, while his record at Wigan could also do with some improvement.
"Here with the Ireland squad, Marco Tardelli has pulled me aside a few times and said I need to shoot more, and the boss is telling me the same," says McCarthy.
"The manager says I have a very good shot on me but I need to use it more, I need to shoot more during the games.
"I am always looking to improve my game, with my club and my country, I could do with a few more goals for Wigan as well."
Meanwhile, McCarthy says he would consider a move to the Spanish league at some point in his career if the opportunity arose.
At the start of his career, the then-Hamilton player was linked with a number of Spanish clubs and his Spanish-born manager at Wigan, Roberto Martinez, has also made sure that McCarthy is known back on the Spanish scene.
"Spain is a top league and you want to test yourself against the best.
"At this moment in time I am happy at Wigan, I am still learning my trade but if something came up in the future I would certainly look at it.
"I am playing in the Premier League week in, week out so I have no reason to move away at the moment," says McCarthy.
3James McCarthy appears in FIFA 13 Ultimate Team, where you can build, manage and compete with your own Ultimate Team. Sign up now via PlayStation Network and Xbox Live. For more, visit ea.com/intl/football/