On Knowing what to Know - Michael Johnstone (Mon 28 Sep 2015)

Self Portrait - Green Peas / Alexandria (Thu 22 Sep 2015)

Mike Johnstone writes:

you only need to know what you need to know

via Mastering Photographic Technique by Mike Johnstone.

And, in the same thought, maybe to help you through any procastination:

you only need to do what you need to do