Keep the language very simple--no idioms (e.g., beat around the bush, drop of a hat, burning the midnight oil, etc), puns, wordplay, abbreviations, or American-specific phrases (e.g., the down low, ballpark figure, out in the boondocks, etc). It might take a little effort and creative thinking to work around all that since those are fairly commonplace in English, but they don't translate well into other languages/cultures.
If you can avoid all those and pretend you are writing in a way that a 5-year-old could possibly understand, then google translate can work reasonably well. Otherwise, the translations can sometimes get garbled and might not make sense.
Then as a sanity check, take the Italian that it generates and run it through the translator to get English again. If it's garbled, you'll either have to simplify your words, break sentences/thoughts into smaller chunks, use alternate words, avoid words with possibly multiple meanings, and/or try to use more specific language.
For example, instead of "out in the boondocks", use something like "in an isolated area". "Isolated" is a better word choice than "remote" in this case, since remote could mean more than one thing.