While I'm not entirely pleased with how the mandibles came out and drawing reflective substances such as amber is annoying, here is an amber pterosaur flying above a cloud of deadly dust.
First big no-no that you've committed here: there's never a reason to mix pixel sizes. You have this dino drawn at one resolution and the dust has been drawn at a higher one; don't do that anymore. Pick a canvas size and stick with it. If you need more space, make the canvas bigger instead of sizing up the image. Try to plan ahead and think of how much space you'll need to fit the idea.
You're not making the best use of colors that you could. I had to look closely to see that the dino was more than one shade of yellow, and most of the shades are so close to one another in saturation, hue, and brightness that they're indistinguishable. In pixel art you work with a small number of colors and each one has to mean something and add to the piece. Next time try going a little darker with your shadows and only add one color at a time. Don't just change saturation and brightness, try shifting the hue a tiny bit too when you're mixing new colors.
Positives:
The silhouette is good, a lot of beginners have a hard time getting perspective right and it seems like you did well in that area. It also looks like you worked off a reference for this so that's another plus. A lot of artists think it's cheating to use references but it's not.
I'm not really looking to challenge myself as much as I am practicing, cause as you can probably guess I am for the most part self taught when it comes to pixel art, though the paper sketches I sometimes do I learned from various drawing books.
If the practice isn't challenging you at the least to try something new, then you're not going to get much out of it. You don't improve
just by doing things over and over, you have to practice with goals in mind.
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Here are a bunch of tutorials I copied from the OP of
my pixel art thread. I highly recommend you check out the Pixel Art Fundamentals link, reading that will help get you versed in the vocabulary and basic techniques involved in making pixel art:
Good luck, I'm looking forward to seeing more of your work.