How do you express your femininity?

You simply just be yourself. Now, you can do things to draw what femininity you have out more. You can do things like wear things that are considered feminine in your culture, be neat and clean, try to speak with purity and clarity, and take up hobbies which are considered feminine in your culture.

The voice is something you can work on. All it takes is practice. If you have a husky female voice or a voice that sounds masculine, there is hope, and usually no surgery is required. Voice surgery should only be done if there are underlying disorders which interfere with your voice, such as polyps, nodules (from misusing the voice), and tissue overgrowth (often from smoking). Even male bass singers can learn to speak in a way that can be taken for female on the phone, all without surgery or even electronic gadgets. If your voice is low for a woman, try to aim for around 200 hz (The G to G# right below middle C), and bring the resonance more into the throat than the chest. For increase resonance more, you can use your swallowing muscles to elevate entire voice box, thus making the vocal tract shorter.