This is my dog. This is the first bit of pixel art I have ever made.
I had a lot of trouble with the head, so I kind of stole one from Paul Robertson. However, it still looks bad. Not really sure how to improve the head.
I feel like the back half should be a bit lower. The piece also suffers from pillow shading, or at the very least, incorrect shading. Why are the eyes casting a shadow? Unless they're intentionally bugging out, they should be safely within the skull!
You're also doing some weird antialiasing at the white part of the neck. Don't do that, it just makes it look blurry.
Things I Did:
Put shadow under jaw to give it more definition.
Made the background legs darker.
Fixed shape of head.
Shaded to more accurately reflect the shape of the dog.
Gave it some chunkiness. Chunkiness is appealing!
Made the length shorter and fiddled with the distance between the legs.