I've been reading the Tao of Deception by Ralph Sawyer. It's a book about Chinese military history and unconventional warfare. It advocates the value of applying unconventional thinking for solving problems, and provides examples of unconventional warfare and how battles were won by applying unconventional tactics. In the book, the author cites examples of how the environment was used to win a battle, or how a clever psychological ploy put the enemy into an exposed situation. and in each example its clear the strategists who chose to go down an unconventional route did so because they understood the limitations of conventional tactics as well as the people employing those tactics.
I've always applied unconventional thinking to my magical practice and how I live life in general. It's the unusual perspectives that fascinate me, because they aren't expected. Going with what's expected is easy. Anyone can do it, but seeking and using the unconventional is fun and allows you to discover possibilities you'd otherwise ignore.
The application of the unconventional to magic involves developing a spiritual practice and process that doesn't stick to tried and true. Thus a person will recognize conventional associations and correspondences, while useful to learn, at a certain point stifle the creativity. The answer is to develop your own associations and correspondences. Go your own way, after you've learned enough to know what the rules are, and how to bend and break them and still get results. You can't explore the unconventional until you know the conventional, but once you know the conventional you also know its limits and you can move beyond the limits to discover new paths for exploration.
The unconventional is part of the unknown, in a sense, because it's not something everyone is doing. It's uncharted, or it only has a few markers to indicate possible paths. And you have to be wary of the paths, because even they can lead back to the conventional. The entire point is to do something original and innovative.