lots of love, playful interaction, encouragement... and chicken treats. but it was mostly time, i'd say. she needed to know for herself that her environment, and most importantly i, was safe. even though she was scared, she was a willing participant, which was crucial (she was always very attentive, like she was always trying very hard to understand what was going on). sometimes, it was just ignoring her while i did my usual activities. other times, it was exhibiting positive attention on her, and minimizing opportunities for the negative.
i also worked on desensitizing her to certain triggers that would bring out fear aggression (which was rare, but as such, surprising when it happened), like reaching for her head, by doing it over and over at spontaneous moments to show her that it wasn't dangerous to her (and giving her treats for good behavior, and a tiny, gentle scolding for bad).
mind you, she was a mild case as far as all this goes, but it still required focused and prolonged attention.