Just wanted to point out, "haven't had lessons" --> self taught, "since a kid" --> many many years of practice. To be fair, even the skilled artists here had to work hard in order to reach the point where they are today.
My first suggestion is to decide on a certain theme to focus on first.
#People?
#Machinery?
#Scenery?
#Animals?
It's best to first decide WHAT exactly you're trying to draw and to focus on it, designating it as your desired specific skill/strength. I'm comfortable drawing people without references but I totally sink with mechanical objects - Must.Have.References. With that said, the rest of my post will be based on how I learn how to draw ppl.
How did I practice?
***********************
A: TRACING STAGE
1. Pick something you would like to emulate/Use a reference of something you want to draw. Collect a whole bunch of books, images, magazines....whatever you envision yourself drawing.
I have a huge collection of images in my hard drive and an equally huge collection of artbooks/manga/comics.
2. Try to copy it as closely as possible. Trace if you have to. I still do when necessary. How do I trace? Paper over paper - (a lightbox would be nice though)
3. Keep doing it again and again until you're able to reproduce it without referring to the original
It doesn't matter what book, image, object you use as a reference. An example: I used Disney movie screencaps when I wanted to draw characters such as Princess Jasmine. I took out scenes of her different facial expressions and body poses. I even bought children books of Aladdin as further reference - coloring books/linearts are particularly useful.
Another example: I liked how Watsuki Nobuhiro draws the folds of clothing and hands. I copied random scenes in the manga of hand and clothing angles. If I wanted a flowing cloak, I would check out Sensei Hiko. If I wanted to draw how a kimono looks like when one is sitting, I look for images of Kaoru sitting down in the manga.
Yet another example: I haven't drawn shonen action panels much so I turned to manga titles I liked for action scenes like BlackCat. If I want to know how a fist looks like when punching someone from the left, I sat down and went through the BlackCat manga trying to find a panel that suits my intention. Once I found something that looks cool, I worked on how to reproduce it - E.g. "Add jagged lines to the outline of the fist, use a horizontal lined pattern in the background"
If I can't that particular image in books/magazines/online images, I use a mirror and use myself as a model.
At this point, you don't really need ppl's opinion or feedback because you have a specific reference that you want to match. You will -know- if your copy isn't similar with the original. Keep working until it does.
4. Once it starts to look similar, start adding your own ideas to that copied subject. "Hmm....let me try a different hairstyle on Princess Jasmine that Disney has never done before. I wonder how she'll look in jeans and a T- shirt." If you're still stuck, have a look at doujinshis or fanarts to have an idea of how fans mess around with variations of the original character
(NOTE: Do watch out and stay clear of yaoi/yuri/hentai in the fandom)
This eventually encouraged me to move onto the other stage......
B: EXPERIMENTAL STAGE
1. Once you feel comfortable drawing "on your own", start experimenting with your own ideas.
2. Start easy, "Let's see how a blond Sasuke-lookalike in a samurai getup looks." Or "Placing a female character in the pose of a reference original image of a guy" There's a lot of variations you can try out
- Even professional artists use some amount of referencing in their original designs so there's no need to feel bad. I call it "being inspired by other works"
3. Feel free to continue expanding, "What if his hair is longer? How would he look?" Asking "what if ....s" helps in testing out ideas.
4. This is the time to start asking for ppl's feedback and opinion of your design/drawing. Keep in mind, opinions about one's art style are a matter of preference and you will find a good mix of negative and positive responses. That's fine.
***********************
My point really is this: Using references in drawing is very common. So common, it's not even funny. I would imagine you would feel rather good once you've passed the tracing stage.
I haven't seen any of your works (have you posted any?) so it's challenging to give you any specific instruction/guidance, thus the general approach I've taken in this post.