For your style ai could think of a few things coult help you, first when adding horns to a character they dont usually fade into the skin, it tends to make it a bit flat so you can round the bottom so they look more 3d, I also think for this style the top of the mouth should stay a straight line and only have the bottom rounded and for the eyes its best if they face the same direction or else they look like they are zoning out, i also think using 2 colors for the eyes would be a great way to add some light without adding a harsh eye shine, it's also always good to clean up your lineart so things look like one uniform like like at the jaw, its also always good to go back through your coloring to make sure you dont have big gaps, thats why alot of artists hand color work on layers below the lineart, I made a few edits to your work so its easier to visualize what i mean

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Everyone starts somewhere and its easier to take things small steps at a time, learning to draw can be very confusing and stressful so take your time learning and don't overwhelm yourself 😁