Disclaimer: It's not guaranteed that what works for me will work for you, but you'll never know if you don't give it a try, so here are some methods you can try out if you're feeling adventurous.
1). Write In Scenes > Word-count/Time-Quotas
Time-quotas granted me less than hundred words a day, while word-count gave me a hundred. But writing in terms of scenes blew those other methods to bits with an astounding 250-500 words a day.
How I go about finishing a scene is to make sure something is changed by the end of it. That way I'll focus on how to tell my story instead wasting time thinking about how long I should be sitting in my chair or how many words I've typed on my keyboard, stuff that aren't really relevant to the story itself.
2). The Opposition/Antagonist Should Be Involved In Every. Single. Scene
From so small it's almost unnoticeable, to right in your face, after reviewing my own writing and also reading someone else's, I've learnt that a scene without the opposition involved makes me wander off into la-la land.
You're better off(in my opinion) either removing every scene without the opposition involved to some degree or thinking of ways to integrate them into the ones that are already lacking. So if you choose to follow my advice, get creative with how they're involved, it doesn't have to be too on the nose, although it can if you want to. Do what works for your story.
3). Use Prologue As A Last Resort To Explain Fictional Concepts
If your story's beginning is fast-paced like mine, and also full of concepts that are exclusive to that one story, because of the dreaded danger of making your action-packed beginning drag, it's tempting to leave out the explaination-part alltogether, or explain it later in the story, but by that time, it's already too late. Your reader needs to understand what they're envisioning as they read, at least a little.
One solution is to elaborate on it in the prologue. Remember, prologues are not bad if they do their job at making your story more digestible, and at the same time enticing to the reader. For me personally, it was a last resort that I was hesitant to execute, but one that me and my test-reader ent up loving in the end.
Just make sure you make it entertaining in on itself, that it can stand on it's own and isn't purely info-dumping. Trick your reader into enjoying it, make them want to know more.
4). Do Not Bite The Hand That Feeds You.. Criticisms
There will always be some person that have something against what you do no matter what, but learning who to take criticism from will be literally magical for your writing. As a writer, seeing your own work from a fresh perspective takes a lot of mental effort, and your test-reader(if good) will get you there way faster. So don't bite your test-reader, cherish them.
But of course we need to distinguish genuine critics from those who don't have your best interest at heart, and what I've found to be the determining factor is how well they themselves take criticism. Those who takes criticism the worst have very fragile egos, and very large ones too. Their big ego can cause them to believe your story is only good if you tell it in their exact way. Stay clear of those!
Another detirmining factor is if they can feel happy for other people. If they can't handle someone else having something they don't, they may do what they can to sabotage you. An example of this is telling you that you'll never suceed(if you have some more examples of this, please let me know, thank you!).
Comment: I may add more advice in the future as they come to mind.