I recently wanted to learn the basics to help my son and came across this article that made the most sense to me.

Pixel Art Tutorial: Basics

https://www.derekyu.com/makegames/pixelart.html

I have come across other articles that are similar in context but not as cleanly laid out.

The article doesn't go into the usage of software though. I think the design work flow, within software, would be greatly helpful in the understanding of achieving a great outcome. At least in a faster manner.

I hope that helps!