Weirdly, I don’t remember this coming up before.
Brian Eno came up with this in the mid 70s as a method for artists to overcome creative block - something with which we are all familiar I’m sure. Made famous initially during Eno’s work with Bowie:
For the 21st century, here’s an online version - wouldn’t mnid seeing the actual cards at some stage though.
http://stoney.sb.org/eno/oblique.html
Super interesting concept. I wonder how effective it is. The first one that came up for me said:
Remove ambiguities and convert to specifics
I’ve always been a fan of this in songwriting. It is common to say something along the lines of “your love is like an ocean” (for example), and to change that that to a direct, “your love is an ocean”. Something as simple as removing the simile/metaphor can totally change how you write the lyrics in and around that phrase. It puts you directly IN the ocean, not just creating ocean imagery.
Inspiration by Musical Entropy is influenced by Oblique Strategies. Worth a try.
https://musicalentropy.wordpress.com/2012/11/05/inspiration-kvr-dc/
Isn’t that related to personal/impersonal perspectives in songwriting? In other words, a tendency might be to have a very personal inspiration for a song (otherwise why would we write it), but the writer may wish to not completely expose their innermost thoughts and emotions around that subject and therefore make themselves very vulnerable in front of other artists and the public. So they might take the impersonal approach … oops see, there I go … I might take the impersonal approach. 
It’s easier and safer to write about a subject with some degree of anonymity, but that also can leave the song quite boring and meaningless. Some of the most inspiring and touching music is clearly a part of the artists soul which they chose to become vulnerable about. Not always, but I think it tends to be one potential hallmark of most ‘great’ music (subjective of course, but powerful and meaningful as opposed to mindless disposable dance/pop for example).