Hello, new user here! I have recently been interested in pixel art (specifically in games). While I am not very good at art (drawing), I want to learn how to make pixel art for video games.
As a starting point I looked up images on Google. This is the image I found to use as a starting point:

DISCLAIMER - that is not my artwork.
From there, I made a variation of that style:

My first question is should I make the size of the sprite bigger?
Also any advice on making him look better?
I then tried to make a walking animation:

I have NO IDEA what I am doing haha. I messed with the upper body a little but ended up just leaving it because I don't have a clue where to start.
So specifically my main question is: How do I make a realistic or simple walking animation? I realize the upper body isn't moving so it would also help to provide some pointers for upper body movement. I'm not necessarily asking for you to completely rework my sprite (although if you feel so inclined...), but I would definitely like to learn and try. I just don't know where to start.
I appreciate any and all criticism and help. I had fun trying, and hope I can learn through you all!