Used informally among friends or in relaxed settings, not in formal writing or speeches. Don't worry, once you get the hang of it, driving will be plain sailing.
Pro Tip 2/3
Optimistic Tone
Conveys a positive expectation that something will not be difficult. She said the recipe was easy, so it should be plain sailing for us!
Pro Tip 3/3
No Major Issues
Implies that remaining tasks or the path ahead will not have significant problems. We've finished the toughest part; it's plain sailing now.