How I learned:
- Start low-res. See what you can draw in the smallest possible space. Choices about a shape or line become binary and easy to experiment with. I'm talking 10x10 px.
- Limit your palette. Try some NES-style monochrome sprites. This will let you focus on shape and not worry about color yet. This will also teach you how to use negative space for coherence.
- Color can get tricky because sometimes you have to draw counterintuitively. There were many situations in some 8x16 sprites I drew where the light and dark shade of blue were used inconsistently in terms of shading, in order to make the shapes more distinct to the viewer. What looks coherent zoomed all the way in will not necessarily look coherent zoomed out.
- Modify existing sprites. You will learn a lot this way.
- You don't need to start with another medium. Not sure why people are suggesting this. You don't learn golf to get better at lacrosse. And frankly IMO pixel art is one of the easiest mediums to self-teach. I have no other visual art talent.
- Draw a class of sprites as practice, don't get too hung up on a specific one. I drew dozens of woodland creature faces in monochrome 10x10. This will help you develop a visual language for what you're doing, shifting pixels so the various sprites look distinct but cohesive in style.
- Legibility is king. Some people prioritize beauty but the player needs to know what they're looking at instantly, at least once acquainted. The sprites in Streets of Rogue exemplify this.
- Skip the guides, honestly. You might be overthinking it. I self-taught fine and I'm no artist. It will take more than a month.
- Remember to enjoy what you're doing. Don't make it too much into a work task with concrete goals, yet.
- Try some 2-frame animations. Some sprites only make sense to the eye in motion.