How to spot episodes. Mine start with anxiety/panic attacks from some sort of environmental trigger. From there my mood shifts either up or down (but usually mixed). It seems I get a bad one every couple years or so.

And I agree with sleep. There is research out now that shows Bipolar may in fact be a circadian rhythm disorder. I have never known a Bipolar person who sleeps like a normal person even when not in a major episode. Most of us are night owls and even prefer to sleep in the day (if we can). I know, for me, my internal clock slowly drifts every day where I go to bed later and later until finally I come back around to going to bed at normal hours (9-11 PM).

If you're interested in a technical talk on that topic, I recommend this video from Dr. Colleen McClung from Univ of Pittsburg's School of Psychiatry. It's very interesting.