When in Rome...try speaking Italian.
Those who speak English as their first language enjoy the distinct benefit of its function as a lingua franca across many communities and cultures, especially in tourism. It can, therefore, be tempting for travelers to forego learning any of the local languages, especially in countries where English is commonly understood.
These days, translation apps make it possible to hold more complex (albeit halted) conversations in other languages, regardless of comprehension. On top of that, speaking in an unfamiliar language can be intimidating, and many people are deterred by a fear of making mistakes or being misunderstood. But learning a few basic words can be an easy way to endear yourself to people and possibly yield some unexpected benefits.
Accuracy is often perceived as secondary to the effort, and attempts at speaking the local language can inspire the listener to be more helpful and engaged. A good strategy is to start with the more obvious and necessary words and, if there is any headspace leftover, expand into words or phrases that could make life easier or dazzle the native speakers.
Probably the most important phrase is, "I would like" when ordering anything in a restaurant. It's very simple. "Vorrei" (vore - ray). Vorrei una birra. This simple word before order ordering goes a long way even if you say the English word for the item after saying Vorrei.
I would avoid using hand guestures, especially one such as the thumbs up, since these can have very different meanings from what you are trying to convey. It would be better to learn the word or research acceptable hand guestures in that country/culture than give someone a rude hand guesture.