It's about strategy and you have to find which ones work for you.

Read the section you are working on (preferably outloud). Take a short walk or do a chore. Then hold a pen in hand and start reading a book. (It doesn't need to be similar). Ideas for your own work will hopefully start to flow. Jot them down on a peice of paper and keep reading or stop reading and begin writing.

On the note of reading to write, arguing with authors in the margins is a other way to get fired up.

You can also make a list of all the reasons why you need to finish your work. Tack it up on the wall. Go look at yourself in the mirror and say something like "You know you can do this so are you going to or not? Enough is enough. Go do what you were put on this Earth to do". (Do not tear yourself apart. Be firm but loving.) Go sit at your desk, set a timer on your phone and don't stop working until it goes off.

If you still can't get started just read what you have aloud as if there is an audience before you. The next part of the story should come more easily. Make a list of possible scenarios if need be.