It's an interesting rollercoaster, preparing for a trip into a place that is so vastly different and exciting, yet can also be lonely and absurd. I still have no clue how to prepare for such a trip mentally. But I thought I'd list some of the things I've done these past days, weeks. Perhaps they one day help someone else going for a trip into the Great Unknown.
Ow, and I will list some physical preperations at the end as well ;)
Mental Preparation
Think about your goal
Why are you travelling? Connect to your inner value, your goal in life. Which may be extremely small and mundane, and can also be of the 'taking-over-the-world'-kind of goal. Connecting to this purpose in your life, and see how your travel plans align with that.
Being in touch with this 'meaning of life' -- which is not a given and not something easy to find -- is essential everywhere, anytime. But especially when you are going away from people you love, to a place you know nobody. I can recommend reading Viktor Frankl's 'Man's Search for the Meaning of Life' in case you are interested in reading more about this.
When do you feel at home?
Are you going to live somewhere, how will you deal with not feeling at home? What will make you feel relaxed, what do you need in order to feel at peace with yourself? Perhaps this means bringing a small notebook just for you to jot down frustration or on-the-fly-poetry that only makes sense to you. Perhaps it means earplugs.
For me, this means bringing some creative materials so that I can create this 'own space' instantly by putting a crayon to oa piece of paper. Ow, and I've loaded up my e-reader with interesting books, both on China and very different books that are not about China, so that I can enter in different kind of worlds as I please.
How will you deal?
One way to prepare, is also to already enjoy things before you go. Reading up on things, history, options. What would you like to visit? And most of all, how will you be dealing with things? 
Things like this will help me focus. Last time I felt easily overwhelmed, I didn't know what to do with all those impressions. And I didn't take the taime to process them well, or at least I could have stayed more true to that feeling and find ways to express them. The random-approach will help. Show what is going on inside and outside of me, without already deciding what it should be like beforehand.
Physical Preperation
The Weather
It might seem bland, but knowing what kind of weather you're heading into is kind of a key. Shanghai is hot and humid. So I'm taking one light jacket and one warmer pullover, which I know I will probably not use.
But weather also influences the kind of physical problems you may encounter. Sun screen. But also indigestion from not properly prepared food. And there are precautions you can bring with you, like O.R.S. And musquito repellant, of course.
While you head to the Great Wall, think about the Great Firewall as well.
I won't go into specifics, as I'm not an expert and there are many places where you can find lots of information about all of this. Let's just say China has specific ideas about internet. Read about it before you go. And consider signing up for ExpressVPN.
Rest
These last few days I'm taking some bike rides through the countryside here. Enjoy the peace and quiet surrounding I call home. I'm taking in huge gulps of fresh air and trying to take it easy this last day before travelling. And yes, I'm restless. And that's perfectly fine.
Ready. Steady. Go!
Are you also travelling, for work or otherwise? How do you prepare yourself? Let me know in the comments!