If you're constantly blasting it over, I'd say ensure that you're only tapping shoot (if even that blasts it over, ensure you're hitting the shoot button rather than the cross button - FIFA and Pro Evo swap them around).

Failing that, ensure you play at least a front two - try to commit the keeper and then pass to the other striker or an open midfielder to put it away., and remember that things like balance, the direction your facing, any directions you're pressing while shooting, etc, will impact your accuracy.

If you really cant score,you should make sure your using the 'b' button which is the red one on the right side,if that doesnt work you should press the rb button while shooting because that will place it more.

I agree with valogoonerman or just sell the game and get a different one if all else fails

When i started to play fifa at first i had the same problem, until i realized that you only have to tap B instead of holding it down. If that fails too, make sure you are having good chances to score (usually shoot from about 24 yards away or less).