I remember when I started my PhD, the write-up seemed like an insurmountable obstacle that was thankfully far enough in the future at that point to ignore - how the hell do you write 40,000+ words about something so difficult? Then three years passed in the blink of an eye, and I found myself standing in base camp, with the thesis fast having to become a reality. For those of you who are about to find yourself in the same situation, here are some tips that I picked up - some at the time, some a bit too late - that might help you get to the summit.
1. Look after yourself. It's an obvious one, but also one that's really easy to neglect. Now, more than ever, you'll need a clear and focused mind to gather your thoughts and ideas into a coherent written entity. That's not going to happen if you hole yourself up in a darkened room, living off beans on toast and noodles. Eat healthily, take time to exercise (or at least get out of the house/office), don't cope by drinking, and leave off the cigarettes.
2. Set yourself daily or weekly goals. I actually found the write-up one of the most manageable times of my entire PhD, because I set myself a daily writing goal of 500 words every day. After 80 days, that would have meant a 40,000 word manuscript, but 500 words a day sounded like a much more attainable goal. Plus, I knew at the end of the day whether I'd had a good day or a bad day - sometimes I wrote a bit less, but I knew it was a tough section. Other times I wrote a bit more, which meant I could take an afternoon or a day off. A thesis seems impossible to write; 500 words is easy.
3. Don't be a perfectionist. I hate to break it to you, but no one really cares about your PhD. Chances are that about 3 or 4 people (not including family) will read it - one of them is you, and the others are your supervisor and examiners. The point of a PhD is not to produce an earth-shattering, game-changing piece of work. It's a training programme, designed to give you the tools and know-how to become an independent researcher. So don't agonise over it when you come to writing it up - note, however, that I don't mean you should just had in any old crap. Do the best job you can, but accept that there are going to be problems with your work, that it's not going to be perfect. If anything, if you can identify the issues early, you can include them as discussion points both for the thesis and the viva.
4. Don't waffle, but make it your own
. No one wants to read a 120,000 word monolith that includes every minute aspect or tangentially-related idea about your work. Make the thesis clear and concise, and the examiners will thank you for not making them work harder. That being said, your thesis is perhaps the one chance you'll get in your career where you have complete freedom to make the writing your own, so by all means go for it. One of my favourite parts of my write-up was giving a brief historical account of eye movement research and how it was developed, from 18th century devices that sounded like torture machines, to modern-day digital technology. It really gave me a sense of continuing a proud scientific tradition, and hopefully that enthusiasm spilled over into the rest of the thesis. Plus, it also formed the backbone of a blog post
a while back, so it wasn't a complete waste of time.
5. Don't compare yourself to anyone. You are not in a class. Despite what I said in point 3, you are still becoming an expert in your particular niche. So don't compare yourself to anyone who's going through their PhD, especially those who are writing up at the same time as you. Everyone's experience is different. Some people write 40,000 words, some people write 85,000 - that doesn't make one better than the other, it just means different research areas have different needs. If you start comparing yourself to someone else, you're going to concentrate on the things they're doing better than you and ignore the things they're doing worse. That's just going to make you miserable and demotivated, and it's simply not worth it.
6. Make sure you have downtime. Not only is it perfectly acceptable to take time off from writing up, it's an absolute necessity. If you don't, you'll drive yourself crazy. Reward yourself when you've had good days or weeks, and make sure you keep up with any hobbies you have. and besides, sometimes a good distraction from work will help you get over any writer's block you might have.
7. Discuss draft chapter deadlines with your supervisor, and stick to them. If, like me, you're constantly clueless about whether or not you're being productive, agreeing chapter deadlines with your supervisor is a great sanity check. It should really go without saying that you need to stick to them - obviously you don't want to aggravate your supervisor, but you also need to give them enough time to read through, make comments, and send it back to you so you can revise the manuscript.
8. It's okay to moan. Everyone who's been through the write up knows what it's like. Newer students who haven't been through it yet need to be prepared for it. So it's okay to sound off on people, but be realistic about it. If people ask you how it's going, and you're actually having a good day, don't moan for the sake if it - be positive. On the other hand, if you're having genuine difficulties, don't keep them to yourself - go and talk to your supervisor, or a post-doc in your lab, or a friend. Chances are one of them will be able to help, and you shouldn't suffer in silence.
In the end, I found the write up to be one of the most enjoyable parts of my PhD. It gave a real sense of closure to the 3+ years, and at the end if it I had something physical and tangible to show for my efforts. I guess it what you make of it, really. You can make it something enjoyable, or you can panic and make a mountain out of it. Either way, you'll get through it - your supervisor (if they're worth their salt) wouldn't have let you get this far if they didn't think you could do it.
So if you're just about to start out, hopefully you'll find these bits and pieces of some use. Best of luck with it; I'm sure you'll do fine.