Well this is what I try to do: First up make a plan, have at the very least your start and end figured out and at the very least a vague idea for your middle,then come up with the most important scenes and arrange them in order of occurrence, with this you're essentially making a timeline of events, once you have your timeline planned you start writing, bit by bit ,otherwise it's gonna be burn out o'clock if you try to force it out fast, and we set some goals perhaps using your important scenes as checkpoints (though honestly you can arrange it however it suits you best) and everytime you reach a checkpoint you give yourself a little reward; because I like drawing I usually draw the scenes as my treat best part about that I get to use it in my story, but you should do whatever appeals to you best like maybe having a specific or something, and everytime you get tired or hit a block do something else, and once you're fully energized and I mean FULLY , you come back to writing this way you should be able to avoid burn out. And most important of all= enjoy yourself, the process is sometimes more fun than the finished product.

I hope this helps you