While your willingness to learn a few bits of the language and to be polite are laudable, I think you may be expecting too much from yourself, and too little from those you will meet. Sure, learn the polite social words and phrases, but unless you work really hard to get to extremely remote places and/or in unusual situations, as a tourist I think you will probably find that many (usually most) of the people you interact with can understand and speak English just fine - often almost as well as you (presumably a native English speaker) can. IME the younger the person you're looking at, the better their English will be and the easier they'll slip into conversation in English. If the person has a lot of gray hair, maybe expect less.
IME few people you will be dealing with (almost everywhere in the world) are really interested in using google translate or other technical translation tools. It just slows things to a crawl and gets in the way of getting things done, it's awkward, and most people do not have the patience for it. 99% of them would rather just use their simple-if-imperfect English as they do with almost every other tourist they see. Only when you've both completely run out of common language skills (they'll have plenty) and patience (depends on the situation) will they be in the mood to resort to gizmos.
I once bought a brand new, expensive (multi-thousand dollar) musical instrument in a Tokyo instrument store where nobody spoke more than a few words of English (and I only spoke even fewer words of Japanese). We got by just fine with pointing and pantomime, writing down numbers, a bit of shrugging and smiling, and a willingness to make things work. I did resort to google translate when we got down to details over price, payment, receipts, taxes, and other small things, but the actual need for that was remarkably minor. I left the shop with my beautiful (and frighteningly expensive) new instrument with a smooth transaction behind me, my only worries were dropping the thing or having it crushed on my way home via the subway.
In short, you will be fine. Don't get too stressed about the so-called language barrier. It's mostly gone, even in places you would expect it to be a problem. You can always resort to google or drawing pictures in a pinch.
For better or for worse, English is just about anywhere that a tourist might find themselves. Don't be too hard on yourself if you can't rattle off beautiful-sounding Italian conversations. Use your hands to express things more than you might at home (careful with gestures that might be mis-translated, eg what we think of as the "OK" sign means something entirely different in some parts of the world...), smile and be as charming as you can be. It'll all work out.
