In addition to Ben's excellent answer, I'd like to highlight another option:
Do not underestimate the power of a writers circle (also called critique circle). These are either websites, communities, or private groups of writers who read and critique each other's work. While they are not always for everyone, I have found that joining and participating in a supportive writers circle can improve writing tremendously for several reasons:
Firstly, you get critiques on your work, often by some seasoned veterans, who will often be quite eloquent in pointing out your issues and points of improvement. This saves you reinventing the wheel by making every rookie mistake they have already made numerous times.
Secondly, by critiquing the work of others, you tend to look more closely to what can cause issues in writing, and you naturally try to prevent these issues in your own work. This often doesn't work when analysing your own work, as you are already too invested in it. This touches on what Ben stated:
Read "with a writer's eye", that is, observe how the text you are reading is constructed, what language the author employs to what effect, and so on.
and
That is, study what you read to whatever extent you find helpful.
While you are doing this, why not share what you learn with the original writer, and do the both of you a favour? Even if you find no flaws, that in itself can be useful feedback for writers.
Thirdly, it is often confidential. Most circles have an either written or unwritten rule not to publish any of the writing they critique elsewhere. This means that your writing will not be publicly available and prevent issues with publishing down the road.
Lastly, it's low entry and non-binding. Most circles have a quid-pro-quo approach, where you "pay" for the critiques you receive with your own. However, other than this, if you find a particular group doesn't work for you, you can often leave at any time and join another. There are also groups with writers of various skills. Some for low-level hobbyists, others for highly experienced veterans, to suit your needs and level of confidence. Although, I would recommend finding a mixed one myself.
Writers circles, in one form or another, have been used by writers throughout history. Often it was as little as two or three friends getting together to share their thoughts on each others works, but now there are large online communities doing the same thing in a more streamlined, professional, way. A quick search will find you a few free and/or paid options which might work. I've also met people who found their peers by enquiring on forums or even their local library.