ok... im going to say this. If you guys tell me diferent things, and i thing what i did its well made, i wont understand. i cant see the error if i think they are all right, that is one problem. The other one, yes, i do not realy know how to shadow the sprites good.
this is where you grow your artistic sense.
you need to understand why your work has flaws, even if your eyes don't think so. We gave a bunch of criticism already, it's your turn to understand it. We can't teach you how to understand, that's your part of improving as an artist.
as a start, I suggest doing something other than sword, since metallic objects have peculiar traits when shading. Go for something more simple, as fruits, or objects that are easily found at your home. This way, you can observe it and try applying them into your work.
the only fruit i had in home was a pear
It´s not what i expected to get from the first time I tried, but ill had to continue placticing
ok... another pear!!!
No. Don't use dithering. It's a very difficult technique to get right and you're nowhere near that level. What you need is fewer colours and higher contrast. I can barely see the difference between some of those colours. Fix it.