I'm trying to find ways to defeat Angels beside simply getting them to look at each other. For instance, in the episodes “The Time of Angels” and “Flesh and Stone”, you can't get a large group of Angels to look at each other. I thought of using a mirror, but that's if someone is fast enough to smash all the mirrors to trap them before the Angels get to them. The only other option is "paradox which would poison the time energy they used to feed."
Angels can also be starved to death - they literally waste away, their forms decaying, looking like erosion. The time frame needed to do so in unknown.
The way they feed is somewhat unclear - in Blink, they feed off the potentiality of the person's "unlived" life in the present, but in Manhattan, it seems more like the people sent to the past are fed upon by Angels in that past, hence the building where their victims are held.
The implication in Manhattan is that the paradox must involve the person on whom the Angels are feeding / have fed. So by dying as a young person before he's captured, Rory negated the timeline where they trapped him, resulting in a paradox that did more than kill one Angel, it virtually erased almost all of the ones involved in the plan.
So the bootstrap paradox in Blink would not kill the Angel, as the events did not undo themselves. If Sally had returned to the old house during the events of the first half of the story and directly interacted with her friend, telling her to turn around or some such, it may have, since it would have affected someone who was a victim of the Angels.
But then they'd probably have to deal with those guys from Father's Day...