hey!
your first attempt is awesome man, you have a nice style! I'd recommend some shading just to add a bit of depth. It makes a massive difference.
For the hair/beard, I'd keep it quite simple, like avoid detailing in individual hairs and treat it like its a solid form.
I started doing pixel art about 5 months ago and what I've come to realise is that less is more (particularly when you're starting out), which took me a while to realise

But yeah, you've totally hit the ground running, can't wait to see it finished! x