Howdy! Something that might help you here is to start looking up some more standard art tutorials. Pixelart can seem appealing for beginner artists (myself included) but it can lead to some problematic art habits and difficulty starting over to learn normal art (also myself.)
Speaking from that experience, it may help to start small with some spheres and cones and cylinders to get a feel for shading and thinking about objects in 3d space, then move on out to normal figure drawings (quickposes.com, google) or still-life sketches (google random objects) to familiarize yourself with drawing normally and build some maneuverability in your skillset.
Pixelart is in essence a sub-set of cartoonism (at least in most cases) and understanding how to draw in a more standard fashion translates to that very well. There's plenty of good books on the subject, but I'd start with what I'd listed and come back for those.
Learning art is going to be pretty time-consuming, but don't give up! There's a lot of fun to be had with art, be it drawing out fun fight scenes straight from your head to pouring your emotions out into surreal landscapes and scenes.
As for the current piece, I reccomend using higher-contrast colors so the skin and hair don't merge together with the skin. Try to set up some cross-bar guidelines (seen here:
).
You can simplify this to a simple cross so it fits the constraints of pixel art, but using guidelines helps ages even for more experienced professionals.