Athena's Sprite Road.

[Hoeloe]

@Gors:

Avoid doing dithering, unless you're: 1-working with an extremely limited palette; 2-is simulating gritty surfaces, such as orange's skin;

Dithering is also used, if someone intentionally aims for a certain retro look (like Sega Genesis graphics). I know, it's not too common nowadays, but i wouldn't say just because something isn't popular, it should be avoided. It's always good to explore different styles instead of just following one route.

Recycle colors. [...] it keeps your work tidy and more elaborated.

...if you are working with a limited palette, yes. Otherwise, why recycle colors, if "you can easily add a new color to the palette with today's technology"?

Dithering is genuinely a difficult technique to use successfully. A lot of older games, even with very limited colours, don't use it for this reason. If you're just starting out, it's probably not a good idea to attempt dithering.

Also, while it's not necessary to recycle colours, it is good practice if it won't hurt your work.