How can I be a good medic?

I play on PC and I have no friends to play with so I usualy play with randoms. And of course they down alot, and I am usually a nice guy and be the medic. But I need help:

What can I do/use to be the BEST medic such as:

The Best Guns (so I can run fast and be able to kill zombies around me efficently so I don't down reviving them)

The best perks (obvously QR)

And what should I do? Like follow people around, not do the rituals in SoE and stuff like that?

Thank you in advance since I might not read responses since I might go to bed soon.