Taking the 70-333 Exam soon? If so, you'll want to check out this book written by Michael Tressler (aka, flinchbot). I found this book super helpful when preparing for my exam (which I passed in April 2017, by the way, with a 975 😉) and it does a really good job of covering all aspects of Enterprise Voice. Hands on experience is the best teacher, in my opinion, but I would recommend using this book as a study/reference guide.
Time to study for my Office 365 Exams. MCSE Productivity, here I come!