Females keep the conversation rolling, nearly constantly make eye contact, have a much smaller or nonexistent 'personal space' of physical proximity to others than males, and almost always gesticulate while speaking. Females seldom make absolute statements. By combining some, many, or all of these traits, it is possible to develop a convincing voice. As for mannerisms, study other women and assimilate body mannerisms that seem comfortable. In time, your own personality will shine, and you will unlearn the crap you had to learn to imitate to survive in a male role.
Exaggeration never works, keep things subtle.
Females generally are looser in body motion and more relaxed over all. Genuine is always best, as is subtle. Females are naturally more relaxed in their muscles than males. Estrogen will gradually do this for you. If you are uneasy, a good solution is simple slacks suits and jumpsuits, that sort of thing.