Thanks for commenting on my pixel art I'll try to improve it

Not bad, but the boy's left arm looks a little weird (kinda like it's broken), as do the fingers on both hands. I don't know if his shirt is supposed to look like that (I can't tell if that's shading, or just a pattern or whatever that image on a shirt is called). The blue and yellow in the potion clash together and don't look good, and the yellow line in the bottom left corner of the potion bottle as well as a few yellow pixels in the bottom right corner of the potion bottle distract my eye since it's clashing with the blue. And you could try to "unify" the colors together (I dunno how to word it) in order to try to use as less colors as possible; since your piece appears to have reached the 15 color limit and only the boy and the bottle seem to have volume, you might as well need to try to reduce the color count and get lesser colors to work together in order to achieve volume for all the stuff in the piece (save for the shadow and probably the background). And as one final critique notice, his right foot (foot on our left) seems unaligned with the left foot; try shifting the foot down a few pixels.

I hope this helps, I tried my best to explain what needs to be fixed as well as provide tips :)