I've found that the best way to be more empathetic is to become a calmer more patient person. Putting myself in someones frame of mind is like taking a mental deep breath after every time they say or do something. I have to let the loop of consciousness run a few more times before allowing my thoughts to become opinions and express them in a response.
I recommend meditation. Empathy is consciousness of self and of others, consciousness is pre-frontal cortex executive function. Meditation is the expansion of self-awareness. When I was younger, sometimes after getting angry, like reeaally angry, seconds after calming down I would think "Shit, there was no reason to get that mad". It's a complete loss of self-control, executive function. The same thing happens after saying something stupid(hurtful) and then realizing it was hurtful(not empathy), if I have the ability to realize I shouldn't have said it, that means if I had just mentally waited a second or two and reassessed the thought I could have prevented myself from saying it. Meditation helps give me this time, stay calm, and assess situations(not only social) before acting. I think if scientists(if they haven't already) looked at the brains of empathetic people and stay calm in chaotic situations they would find the front of their brain buzzing with activity.
2. Voice - I'm about 1/3 the way through a huge singing course
3. Empathy - I want to get better at really putting myself in someone else's frame of mind.
4. Maybe pick up basic conversational skills in another human language, but this one's at the bottom because I know how much time is involved.