Craig,
Those are both good posts by Dan and Matt; I think you owe them both a beer for taking the time to post links (especially Dan; two beers for him).
But the thing about experience is, when you need it the most; you haven't got it.
I had a ladder slip out from under me during my first six months of window cleaning; I think I was over confident and tired; while cleaning a window above a porch; using the ladders at a slightly steeper angle than I should have.
Luckily enough I was okay apart from some bruises and scratches (I'm a Geordie); the fall would've killed or seriously injured a 'Southerner'.
Personally, I'd still canvass houses with awkward windows, if I were you, just explain there'll be certain windows you can't clean at the moment; till you get a pole system.