If that's the case, I don't want to sound like a jerk or anything, but all you can really do is keep trying and keep working on your accuracy. I know this may be easier said then done, but it's really the best piece of advice I can give. It's really how I increase my skills in gaming (and other things in general).
Although, to be fair, I never beat Bomberman Hero (I mostly watched the bro play it), so that's really the only piece of advice I can give.