Marine [C+C]

[Frank]

Hey guys, what's up?
So, this is my first attempt to do an pixel art, could you guys give me some critiques or even tips? Thanks! 

[PsylentKnight]

I'm pretty new here as well, but I'll help you out as much as I can. 

The main thing is that those lines are extremely heavy. Try to define things more with shading than with black lines.

The shading is pretty rough around the edges. It could just use cleaning up in general. There's a lot of places where it escapes his outline or where the background isn't even colored over. It also seems like you're just doing a gradient from one side to another and not paying a lot of attention to how light would actually react on his features.

It would help if you told us what you are going for... if you're going for realistic, the proportions are way off (legs are too short, arms too big, etc.). It looks like you're going for something more stylistic here, but context would help a lot.

That having been said, its not a bad piece at all. Your shades have good amount of contrast between them, with is something a lot of beginners do wrong. The colors aren't eye wrecking like my first few pieces.  His form is good. I like it, but it could use some work.

[Zizka]

Here, I'll give you the advice someone gave me:

APLAD!!! Always Put Lights Against Darks ... A P L A D !!! You NEVER have to use "hard" outlines to show edges.... Look at the corner of the room that you are in...... How can you tell there is a corner there? CONTRAST!! even though the walls are painted the same color... you can see the change in light against dark that creates the edge for you!!! Outlines are for coloring Books! (STAY INSIDE THE LINES!!) lo

[Frank]

@PsylentKnight

Thanks alot buddy, I was pretending to keep that "style thing" but you're right, that was just lazyness of my part... I need to study proportions because mine are very very odd, thanks for showing me the mistakes, I appreciate that

@Zizka

Thanks! That was very useful 
About the rough brush, I'll not repeat this mistake though

You guys rocks!

[PixelPiledriver]

Nearly all the lines are the same thickness and color.
If you really want to use lines try varying the weight a lot more.
Use a logical pattern to dictate the thickness of any given point on the line.
Directional, balanced, detail hierarchy, border vs inner , compression, overlap, etc.
Google around for other ideas or come up with your own.
Also do this with the other properties that lines can have.
Here's a quick first pass for example:


Otherwise if you don't want thick borders for all divisions, this just looks like a preliminary step and you should start popping off the sketch structure and cut into it.