A good book is your friend.
An interesting piece of advice I once got about work and any other travel was to go to a local shop, buy something (Anything, really) and a local paper. Always ask for a bag. Then, walk around with local paper visible and local bag in hand. Much less likely to get any hassle.
Overall, though, have a book. I spend an age in hotels, airports, etc, and a book is almost always with me. Oh, and don’t be afraid to strike up a conversation with someone.
Some more tips;
Ask the reception where to go and eat/drink. Never failed to find somewhere nice on my travels this way. (Am really looking forward to going back to China next month for those soup dumplings…)
Do not, whatever you do, drink on your own in your room. That way danger lies.
Did I mention a good book?
😉