For Foreigners who moved to Japan, what advice do you wish you had beforehand?

I have lived in Japan for over 5 years now and run a business. So many things I look back and am glad I did right (becoming fluent as soon as possible, holding onto all of my invoices/receipts, keeping all my contacts from former and previous work, working with a local tax accountant as a freelancer, etc.), Some things I wish I had known or considered earlier (avoiding certain types of investment accounts, understanding particular culture on gift giving/receiving, etc.)

If you could step back in time to your even more gaijin-self, what advice would you give them?