Hey Mariana, I like this first figure you drew, it has a nice gesture and pose. I think if you want to improve, you need to think about the structure of the figure. It will help you give it a 3D feeling to your drawings. I did a draw over to show you what I mean. I hope this helps :)

Even if you use a mechanical pencil you can have differente grade of mines (Riccardo Federici use mechanical pencil for his stunning comic's pages but whit a quite soft mine) For the hair, in the portrait course, there is a video that esplain how to draw hair in the way I told you As far as textures are concerned, the same applies to hair as to feathers, fur, blades of grass, etc. Andrew Tischler explains it well in this video. https://www.youtube.com/watch?v=OKM5OUlxsdg In his channel there are also a lot of nice portrait videos. :)

I see that you've done well in line department. Thus I will advice you to go for form recognition. Some people or artists call it differently, but basically it's the skill to picture the form of a subject. It's the immediate skill to acquire after you get your line work intact. It's the thing that makes a flat surface look like a 3d object, and I argue it's the best single thing you can learn to improve your art skills. Stephen Bauman does a great job in this, and you should see his work (the attached image is from his Instagram page).

Hi Mariana, the gesture is very good, well done! What kind of pencil do you use? It seems to me that in the drawing of the angel you struggle a bit with the lines, maybe you should use a softer pencil to be able to draw more fluid lines. If you're not sure, first use a very light stroke to sketch the lines and then go over them with a softer, more pronounced stroke. And if you think you've made a mistake, don't worry about using the eraser - I know a lot of people say you should never use the eraser, but that's silly and just leads to a lot of frustration. Don't like a line? Instead of going over it to try to correct it, erase it and try to do them again. A friend of mine (Francesca Resta, if you google her you can see her covers, she's very good) uses a very interesting and practical technique for her personal drawings. First of all, she uses a paper that stands up well to erasures (so it's quite heavy). Also a coloured cardboard from school is good. When I was studying life drawing I used a lot of grey and brown ones to draw animals. Great result) and a soft pencil; the secret is to be able to erase easily. She starts with a very rough sketch and corrects it until she is satisfied with the base. Then she erases it so that only a slight trace remains to be followed. On this trace she draws a more detailed sketch until she is satisfied with the design, at which point she erases it again leaving only a trace to be traced. Using this trace she creates the final design, with clean lines and details. At this point she decides whether to finish this design with shading or to lighten it a little with the eraser and colour it in with pastels or watercolours. Personally, I work differently but I think his method is very good if you are afraid of making mistakes and want to be able to make corrections or changes. Somewhere I had seen a video in which he showed the process but I don't remember where he posted it, maybe on her facebook page. The portrait of the manga girl is very nice. For the hair, however, you don't need to draw every single curl. Draw the approximate shape of the hair mass, then define the shape, as if it were a single object (where the shadows and the main light parts fall). Keep it light at this stage, it's just a base. When you are satisfied, you can suggest the texture of the hair. In the shadows you won't be able to see much detail and in the highlights the curls will catch the light. When representing a material you don't need to draw every single detail, just suggest them: the viewer's brain will fill in the holes in the texture. Not only will it be easier for you but the effect will be more natural! :)

Both drawings look great I think and already beautiful. :) I agree with Yiming Wu that it would be helpful to know what makes an illustration beaituful to you. There are so many factors that make an illustration appealing: composition the structure with shapes (e.g. unity in variaty, interesting shapes...) color emotion and storytelling I am sure there are many more. So if you don't have a field of interest, study artists you like and find out why you like them (or post them and we can find out together :D).

I like how you abstract the hair :D. The "volume less" hair shape has a great contrast against the face. I think you are doing great on this. As far as practice goes, I think you are doing fine. If you say want to make "beautiful illustrations", why not just refer to those artists you like most? Find their images and maybe try doing some studies so that you can get closer to what you think you want :) Keep going!