Writing goals are essential to getting anything completed. The main reason aspiring and frustrated writers fail is because they cannot find or make time to write, or if they can, they do not have a viable goal to reach for other than the concept of having an idea for the story and wanting to write it. Now wanting to write something is awesome but that's the easiest part, having an idea is even better but it's still kinda easy to have an idea. What matters is getting that damn thing completed!
There's nothing more fulfilling than just getting that beginning in and introducing your awesome character (you know, that scene at the beginning of your manuscript where the character has a long look at themselves in the mirror and you get to describe their hair color, skin type, bone structure, and what gemstone their eyes match). After that, you get to set the plot rolling by writing the catalyst scene that throws your character into turmoil and jeopardy and might even introduce them to the dreamy love interest or some other important character who is quirky, or cool, or tortured, or terrifying. There is such a RUSH in being able to breathe life into those scenes you've been rolling over in your head and at that point you can't stop writing!
The words just flow from your fingers. You find yourself laughing as you write or smiling smugly at your words. YOU ARE A MASTER OF WORDS and you get such a thrill at knowing how everyone is going to read this story and... and then...
The feeling leaves. It starts with hitting scenes that just don't excite you. They're important scenes but they don't feel right. You know you can come back and fix them later because of the rule of NO EDITING the first draft. Still, they're not as exciting as the scenes you can't wait to write.
So then you leave it a few days and then try coming back to work on more interesting scenes hoping to fill in the less interesting scenes later. That works for a short time but then even that loses it's luster. Writing becomes less and less every day, and what once was a torrent of words has become a drought. The manuscript gets put away and nothing more gets written.
That's burnout... fizzle out.... whatever you want to call it.
A good way of fighting burnout is by setting wordcount goals and making sure to meet the wordcount every day. It locks you into moving forward and even if the writing is bad the urge to turn back and delete or edit is curbed because you need to keep those precious words on the page so you can meet wordcount. It's the whole reason why National Novel Writing Month is so successful.
Sometimes, though, you even reach wordcount burnout! D: D: D: It's like, that goal of 2000 words becomes a goal of 1500 which becomes a skipped day which becomes a weekend off. Then it gets depressing when you find you haven't reached your weekly wordcount and it becomes easier to declare oneself defeated.
The only remedy I can see for this, if one does not want to abandon the story that is, is accepting the dwindling wordcount as a victory over writer's block rather than a failure to meet the self imposed standard. Writer's are naturally skittish creatures and it does no good to feel inadequate and depressed over something like the number of words written per day. Feeling like a failure only encourages giving up.
It's better to suffer a week or two, or even a month of writing days where only 200-600 words are written and trudging towards a second wind of epic writing than it is to become frustrated and give up completely on a manuscript when a daily wordcount of 1000-2000 is not met. Accepting the tiny wordcount results in a constant movement forward. The alternative of feeling inadequate and abandoning the manuscript only ends up in ashes and broken dreams.
I know they say "don't force it" but if you are really serious about finishing a longform manuscript I think you should force it when you've hit the wall. Squeeze out 200 painful words every day, even if they're words you are ultimately gonna overhaul or delete. Nothing about writing is easy, and pushing yourself to your limits even if your brain is tired, can only serve to toughen you up and prep you for sitting with a manuscript for the long haul.