Hey here's some spriting tips (well pixel art in general)
-Keep Practicing, even Riceeman and all those other good spriters on PC started somewhere.
-Click the Zoom button a lot, although you probably know this
-ALWAYS KEEP NINTENDO SPRITES WITH YOU. That way you can use a pallete off them and use it as a reference to see what shading techniques nintendo uses.
For example, Peawee is green and yellow, so I would have a copy of Xatu for a pallette, and I would have a image of a cherubi sprite to see where I should shade and how I should draw Peawee because Cherubi's body type is similar to peawee's/