Ready?
It is a simple one
Option (or ctrl for windows)) + left or right arrow key will move your cursor to the start of the next word (when typing).
Option (or ctrl for windows) and up or down will move you to the start or end of the paragraph (when typing)
I can't believe I didn't know this sooner (I probably wasn't paying attention in class when they covered this part of how to use a keyboard 101)
What other keyboard hacks do you know that make writing easier?