Hey Yan, stuff is looking good. I like it. As far as crits and comments. I would say to maybe just take a little more time when you're drawing. Think about the lines a little bit before you place them, make sure they have a purpose. Besides that, keep up with the life and photo studies. You're on the right track!
I think you are doing a fine job with these, but you can push them much further and improve faster if you really slow down and try to get as detailed as possible. I learned this from taking lessons with Jason Seiler... It's better to see if you can get one piece to look really realistic ( maybe photorealistic ) than to do a bunch of studies that aren't to that level.
hey i see a good amount of work here. keep up with the studies, especially those color studies. Color is really a vast topic and think picking up James Gurney's Color and light would really give you a nice start. But you're doing good! keep them coming!
hey :] your digital studies look good, keep doing them regularly and i'm sure you'll improve in no time. i would also say do a lot of traditional studies, like figure drawings, a book i would recommend reading is the 'vilppu drawing manual', you can find it easily online.
keep updating your sketchbook, i will watch your progress!