How to write papers fast and efficiently? First, my question is not about how to write a good a paper, since there are already many guidelines on the internet, e.g. this one.

What often happens to me is: I designed algorithm, did all the experiments, and got good results. Now, I only need to write up the results to submit. But I just feel I can't do it, or at least not efficiently.

Although I have everything in my mind, I just stare at the screen and can't write anything. I just can't do it. And this leads to procrastination, which I hate so much.

Sometime, when I was doing the experiment, I thought I should write this way in the paper, and it should be very awesome. But when I actually wrote the first few sentences, they were just crap. 

I thought I would start by describing the core algorithm first. But I didn't know how to present the idea, so I ended up polishing the introduction first, etc.

I'm not a new researcher; I'm already nearly one year into my post-doc, and have 6 papers published. It never took me less than a month to write just a 10-page paper, after several iterations, while some of my collaborators can write a paper in just a couple of days. 

I thought it would be better with experience, but it didn't and I'm really frustrated with myself.



UPDATE

I think I'm suffering from the so-called ''blank page syndrome'' (or white page syndrome), but I'm not sure.
I'm not sure if it helps, but here are two ideas that work for me (sometimes).


Don't try to write the paper in its order. Instead, start from the technical parts. This is simple - it is just writing your algorithm. Now, once you try to write the algorithm (and abstract it from code into pseudo-code), you will get stuck because something is missing (notations? a neat observation? a cool idea that makes things clearer?); note these down. Then, expand on the things you wrote down. Another way to begin is with the "cold" facts: the numbers, the experiments - just write the details down in the most dry way...  (After the technical parts are written, move to writing the introduction and conclusion; by that time, you will have already broken your "writer's block", and the writing will flow much easier).  

tl;dr start with the most simple (and technical) parts just to make the writing start. 
Writing a paper is telling a story. You can't write it down? Try this - tell "the story of you paper" to someone else, say, a colleague or a family member. Do this twice or thrice, until you have a complete "story" in your head, and you gained some practice in telling it. Now, writing it down (just following the conversation you had with real people) may be way more simple.




Addendum: This is not a competition. Writing a paper well, takes about a month. Writing a good draft takes at least 2 weeks (of intense work!). Of course, some people can pull an all-nighter and come up with a paper. Don't pay attention to those, they are at the tail of the distribution.