Mario-inspired Sprites

[Sirroelivan]

I've been meaning to get back into spriting after a half year long break. Do note that my only spriting experience is with Picture Wars
(a sprite-based forum game), so the quality of my sprites is on the low side.
Nevertheless, I wanted to show these sprites, which were the last ones I made before my break, to garner some tips and advice before
I start again.

It's basically just a basic Goomba-like enemy, with a helmet and a wing upgrade. There's also a mage character (my favourite sprite) and
a pipe.

[sakket]

helmet looks like a beanie to me. needs some kind of earguard contour I think

[Shrub]

Ugh. Gradient gradient gradient gradient gradient!
You need to be more adventurous with your shading.

[Twirly]

First of all, like shrub said, gradient shading is a taboo ;o
Also you need waaaaay more contrast there and you need to get rid of those interior outlines, they make your rather small sprite look cluttered.
To show you what I mean I made a quick edit of one of the goombas:
->
And yeah I also changed the stance a bit.
Edit:
added an improved version, with more unified palette. Try to unify your palettes btw :p

[Sirroelivan]

Ah, thanks for the advice. I admit to my shame that I have been far to hesitant in trying new things.
I'm going to resprite these guys along your guidelines.