Hey When did you start drawing?
I love your portraits, they are really beautiful
the Apple, Phone and bottel are too sketchy, blurry and smudgy for me, but since its not finished yet... do you have finished ones?
the arm looks quite great, especially the fingers/fist, ...the only thing ive got to criticize is the upper arm, which looks a little bit to broad.
Uhm where to start, first of all you will need some books which will help you out on your path, i highly recommend these:
Figure Drawing for all it's worth- Loomis ( kinda hard for starters in my opinion though)
Drawing Head and Hands- Loomis
Succesful Drawing- Loomis
Glen Vilppu Drawing Manual
Constructive Anatomy- Bridgman
While there are many other, just pick some of these and stick to them for a while.
You told us that you've been drawing for seven years, well that had to be like 1 drawing a month or less, because you still are in that "starting zone"
Don't get me wrong i'm not trying to insult and all i wish is the best for you.
So what i'd do in your place is to really work that sweat, you have to be drawing constantly atleast an hour a day or more if you wan't to become any good at it. Unfortunately drawing is not like riding the bike the" once you'll learn you never forget" does not apply here. It's a gentle subject that needs to be taken care of. Even weekly breaks will show you how much rusty you get after not drawing for those seven days.
I'm a self taught person, so i know what you're through, and ofcours eyou can achieve a succes while learning all by yourself, i highly recommend attenting some kind of course, atelier. It has 2 main purposes:
1) it will help you grow much faster through constant crit and help of your teacher,
2) it will make you practice more often, which is a big win itself!
I'd roll to one of theese if i were you, even if you won't find it really cool to learn how to " render a photo " with charcoal or paint, they will teahc you the foundation for sure. And it's really the only knwoledge you need to start your artistic journey, as your own imagination is the only limit of how cool/crazy/beatiful piece you can make.