Samu-kun wrote:
In my experience with drawing, I think the only way to get better is to just stick with it even if the results are bad.
This is definitely the important part. Whatever else, don't stop practicing.
And as Samu-kun mentions: copy stuff you like. Copy stuff you don't like, if you think it's good. A lot of people get this crazy idea that copying is wrong and they won't learn anything, but so long as you're actually copying and not tracing, it's likely that you'll learn a lot about where your favourite artist places what kind of line, how they vary colour, what volumes they try and portray and stuff like that. Don't pass it off as your own and it's perfectly fine and pretty good practice.
Also important: show your drawings to other people and take on board the advice they give you. Don't hide your stuff away 'cause you're embarrassed, or you might find that you're continually making the same mistake and you never noticed. Don't show your stuff and cherry-pick only the positive comments, because the ones which complain about particular parts of your drawing are the ones you're more likely to learn from. (Ignore anyone who's being outright insulting, of course.)
Samu-kun wrote:
The only way for you to get better is pretty much burn anatomy into your head through thousands of repetitive actions. Once you've done that, then you can begin to draw your own stuff.
I would add that IMO it's generally more useful to learn 'proper' artistic anatomy than learn from ultra-stylised stuff like manga. Once you've learned how the human body actually goes together you can set about stylising it to suit your tastes, but if you don't learn it, then you'll end up making some silly mistakes that make your work look a bit odd.
(The three hardest parts of the body to draw are probably the face, hands and feet. All three are particularly complex groups of muscle and bone. Everyone draws faces; don't neglect the other two when you start practicing regularly.)
Samu-kun wrote:
Third, draw fast and impulsively. Put little emotional investment in any one of your lines. Your lines will never come out smooth if you're too focused on drawing the perfectly shaped line. It's actually a lot more quicker and better looking if you draw ten quick strokes and then decide which one looks the best instead of agonizing over making the single perfect line.
One thing I found helped me a lot was leaving pencils entirely and sketching in ballpoint pen. You can get a lot of line variation out of a good ballpoint - I mean the ones with thick, sticky ink where you have to press to make a line rather than the ones with free-flowing liquid ink - and the best part is that you can't erase it, so you have to live with what you've already laid down. It means you
can't agonise over single lines, you're forced to just get on with it and make the best of what you've got, and that helps get you over the "must... be... perfect before I continue" problem.