She's talking about novels but this applies across all writing, I reckon.
"Wendy Nelson Tokunaga: Common mistakes I’ve seen include starting the story in the wrong place (e.g. starting at the very beginning of the story is not necessarily the best strategy); opening with a scene that is too mundane and thereby lacking tension (e.g. the character wakes up, has a cup of coffee and ponders the start of his day); loading the opening with too much backstory and extraneous details; and using an action scene that serves no purpose other than the mistaken assumption that any “exciting incident” will draw in the reader."
Taken from here via here via Margit Keerdo