4) Be like Dumbledore -- Withhold your backstory until the very end:
J.K. Rowling has said that if you were to put all the multiple drafts of the first chapter of Philosopher's Stone together, you'd have the whole story from the very beginning. The fact that she got wise and so judiciously cut out all that backstory from the start is a huge reason as to why her novels became the phenomenal success they did.
Donald Maass, the great literary agent, says "Backstory is called backstory because it belongs in the back of the story." J.K. Rowling intuitively aced this lesson.
What would Harry Potter fandom be without the search for what actually happened in Godric's Hollow? Who was Snape truly loyal to? And how would Harry defeat the greatest dark wizard who had ever lived?
All these questions were dragged out until the end of the series because they all involved backstory which had been withheld until the reader was dying to know.
Don't dump it all on your first page, your first chapter. Weave in enough backstory to keep your reader from getting confused, but then withold it until they are begging for the knowledge only you can give.