How to prepare for long-term dissertation fieldwork?
The most relevant advice (about the research, not life in the field) I can give is to keep on top of the analysis as the data comes in, and do not stockpile data in the hope that you can make sense of it when you're home. Analysis will reveal gaps and problems, which you need to address before you go away. Though if you're stuck with a rigid methodology where everything has to be set up before you go and then you just grind through the questionnaire, then you have my sympathies.