First, I suggest Strategy Safari by Bruce Ahlstrand and Henry Mintzberg. Link is to affordable kindle version of its first edition. I haven’t read the (very expensive) second edition but it sounds pretty much the same. The book describes the ten different “schools” of strategy. Most of these were created by consultants to sell their analysis. If your goal is to write reports for businesses, this book will give you an idea about what that looks like.
The types of strategy I focus on falls into what that book describes as “positioning” but it isn’t the report writing kind. It is the do-it-yourself types, where you teach people how to gradually improve their strategic positions over time. To learn about this type of strategy, you can read this book, The Golden Key to Strategy.
However, I find that very few people that do the kind of my kind of strategy go into consulting as such. Most end up finding opportunities to start their own businesses and growing them. I did that (building an Inc. 500 company) before getting involved in teaching it, but more serious students go into training and then into business. Only one does straight consulting but that is political consulting so it tends to be more like running campaigns.
For those who are interested in training yourself, we do offer an on-line course for certification, but it won’t teach you how to write reports for people.