That's a great first piece doing digital paint sketching. But something to think about would be your values, first and foremost. It feels pretty low contrast right now and therefore not as three-dimensional and solid as it could be. It almost looks like a pastel drawing. Which isn't necessarily a bad thing. It's a valid style choice. Perhaps choose a more simple subject for future exercises. Just stick to heads and shoulders for now and focus on sculpting the forms with light and shadow. And stick with black and white paintings for now and don't worry about color until you have more control of working with pure value.

Hi Sara, under the write reply box, on your right far side, you will see the small mountain picture icon. if you click on it, you will see the mouse cursor changes into hand shape. click on it and click browse file and click what you done. for a smart phone.

These are very good. i like how you're altering the proportions to fit the character. Even if is the same person you're varying the designs to better represent it. Very good! You're also getting more and more likeness as you sketch more. Keep experimenting with shapes. The Snoopy Dogg ones are the ones that show less likeness, but I feel they were the more productive of your studies because you really explored his face. You varied head shapes, sharpness of the face, proportions, angles... and as you're doing that you're discovering new possibilities and learning what works and what doesn't. Nice work, keep drawing and best regards.