Write everything down. Get in the habit of making good notes. The notebook has to be thin enough to stick in your shirt pocket or hip pocket, so you always have it with you. Do a section for finances. Write down every expense, make note of every currency exchange, including the commission and the exchange rate. Do another section for language learning. Jot down words you want to learn to say, words you can’t quite understand, whole text phrases you want to memorize, etc. Depending on the stage of your work, you might want other sections for interviews & cultural lessons, another for prayer requests & praises & devotional thoughts, another section for contacts & addresses & people with whom you’d like to follow up.