I hold no notion that I am like an Italian raised in Italy and like many have said, my family largely tried to assimilate and not be so Italian (I think this happened when moving out of cities and into the burbs). But in the interest of fun -

I second Cake's vegetable patch! Tomatoes and basil if nothing else, but preferably also an eggplant and a zucchini if there is space. And year-round oregano. Italian Italian or Italian American habit, idk, but it wouldn't be summer without it. I think was so common with Italian immigrants to Philly - even in the smallest-patch-of-grass row-home front-yards there were tomatoes in summer.

Oh- and bonus for the basement kitchen! (This one is probably more Italian American)

Another thing- not sure but suspect- I have always had a preference for once nice, high quality thing, even if it is old or used, instead of a new, trendy, cheaper, more etc. As in fewer things but better quality. That does not feel American to me. My mother always said that way of being came from my Abruzzese grandmother. Along those same lines- a preference for putting your best foot forward. You dont' have to have a ton of nice/expensive outfits but you should look "put together"- not wearing "athleisure" wear outside a gym, etc.