My pixel arts

[Ak1rashi]

http://imgur.com/a/PV5my

[DracoDragon42]

here is the images that you posted

[kilenc]

here's a few things I notice in a quick glance:

1) different pixel sizes on your 3rd image. different pixel sizes makes a work look sloppy and unfinished
2) no shading on the 2nd and 4th image, or at least nothing noticeable; makes them look flat and unpolished; try finding a light source and applying shading from there, there should be some good tutorials on here
3) line work is pretty sloppy on 2nd and 4th image, a lot of pixel noise which makes it unreadable -- trying sticking to single-pixel wide lines if you can, and continue from there
4) the first one has some really good shading, but its hard to see some of the detail due to its size--maybe choose some more obvious forms?

don't take any of this as law, btw, this is a really quick look

[odedrt9]

I don't know about the 3rd but the first one is almost exactly the same as the sprite from a youtube tutorial so claiming it as your own isn't okay.

There are clear differences between the 1st and 3rd to the other two, I assume the 2nd and 4th are your own.
And as @kilenc said they lack shading and contrast. There are plenty of tutorials on these subjects, you should watch some.

[Roach]

@odert9 How do you know he isn't the one that made the tutorial and he's just testing you?

[DracoDragon42]

https://www.youtube.com/watch?v=y5JEc-A8PzY
dis video that first one comes from
I saw this video a while ago and dis is what i made from it

dont do exactly what tutorials say, just do something made in a similar way
edit:
another thing i found, i see you used certain parts of each character for your 3rd one...

please post your original art s that we can help you.