Voice Reel Tips?

Hey to anyone with voice acting experience, lots or little experience, any tips? I am actor as a hobby, so I have some experience with vocal work, and I just bought a mic. I've always really wanted to get into voice acting but I really just don't know how to get started.

I wanted to put together a voice demo reel of a couple different voices or characters I can do, but honestly I just need advice. Should I just do a variety of voices I am comfortable with or should I try to do character voices or impressions?

I also am not a techy and know practically nothing about audio engineering and audio quality stuff so any tips on that would also be super help!

Thanks!