As a PhD student, writing is one of my main activities. I've been trying to improve my academic writing over the past year as part of my PhD journey. Although I haven't had to face a giant writer's block yet, I do remember staring at a white screen for hours and hours, trying to write an abstract, but always deleting parts and trying to start over new. With a few basic principles, I've overcome this slight panic which I feel when I'm faced with a new document, staring at me in all its whiteness.
1. Don't postpone writing
Don't wait until you're in your last year and need to start writing your thesis. Although this statement is common knowledge by now, there are still students who wait until all their experiments are finished to look at their data, analyze them and then write about it. By the time these students reach the point of writing, there is quite a burden on their shoulders. Students like me, who are funded from outside university, need to write partially finished reports whenever a deadline of a part of the project is near. This pushed me to start off with the "easy" writing: the description of every single test which I've been carrying out. An introduction to the test setup and measurement methods came along with that, and without noticing I had some basic material to describe my experimental work.
2. Learn from your examples
There's nothing wrong with being inspired by a great paper or a very clear thesis. The outline of my papers is usually tied to a strict scheme since I have been mainly describing my experiments, but I've been inspired by other papers that describe their experimental program very clearly. When someone has a good and structured setting out there, it's an ideal opportunity to learn from it and use it as a basis for your own writing. Your final product won't look anything like the original.
3. Have material ready
I have probably more (not-so) random documents on my computer with loose ideas, citations and copy-pasted pictures and paragraphs from papers than I have finished documents. I love having material ready and being able to start brewing a story from some ingredients. It feels much more motivating to me than to be staring an empty document.
4. Body first
Don't bother finding the perfect opening sentence for your paper. Just start with the core of your writing: some background information and literature review, and then off to your own contributions. Once these thoughts are out there, it's much easier to write an introduction and conclusion which embody the main ideas of your piece.
5. Let the ideas flow
Try not to correct yourself and reread too much while you are typing out your ideas, as this will only slow you down. Emptying your head first helps to let the ideas flow out in your writing. You'll be proofreading anyway later on, so you'll still have plenty of opportunity to correct and improve every sentence. However, having an entire part written, will help you keep an eye on what really matters: the flow of the story, not a collection of perfectly written sentences.
6. Explore different facets of writing
I've always quite liked writing, but I used to keep a distinct line between my creative writing and my university stuff (which I didn't enjoy writing previously). Over the past few months, I've exploring as many facets of writing as possible: writing poems, writing my diary, keeping this blog, trying to force my thoughts into 140 characters (and I hope to add writing short stories to this list soon as well). Having the habit of writing helps all possible forms of writing, academic writing included. Writing can be lots of fun once you've learned to appreciate it.
7. Fresh air
Still staring at a blank sheet, no matter what you've tried? Then don't be too harsh on yourself and go and get some fresh air. Play outside, have some fun, sleep over it. Tomorrow gives you another possibility (assuming you've been good at planning and you're not writing a few hours before your deadline).
What helps you to avoid staring at an empty document and gets you started to write?