Some other tips that wouldn't fit the image:
- Keep you color count low (less then 32 colors).
- Consider large areas with flat colors, so the eye can rest from details.
- When you need to fit too much detail in a small area, consider changing the drawing so the thing you are drawing has a simpler design.
- Avoid cylindrical or too many round shapes, they are hard to portray in pixel art. Cubic volumes are easier to draw.
- Use silhouettes to show what you want and keep the internal area low-detailed.
Again, a disclaimer, I'm not claiming this is the right way of doing stuff, it's just the way I do it.
About the dither: I'm not against dither or anything, it's just that excessive dithering is not suitable for my pixel art style. And I use it occasionally or when the palette is too restrictive. I guess you could say I'm dither-curious, maybe one day I'll find a dither I really like.