There's just no comparison between in-season, local tomatoes that you get in Italy and the supermarket crap you get anywhere else, which probably accounts for most of the difference.
Your best bet is to look for heirloom tomatoes, in season. Failing that, try New Jersey beefsteak tomatoes, again, in season. Or any of the "vine ripened" tomatoes you see in fancy grocery stores, although every year those get harder and more tasteless. Finally, if desperate, and you have no choice but to use supermarket rock tomatoes, at least get plum tomatoes, which manage to retain a tiny bit of flavor.
Bruschetta is just:
- yesterday's bread (ciabatta or a French baguette), thinly sliced, brushed with olive oil, and grilled or toasted
- chopped tomatoes
- garlic, basil, Italian parsley, and any other tasty herbs you have lying around (Oregano?)
- The finest extra virgin olive oil in the house
- Salt and pepper to taste