Documents

Passport & correct visas
Emergency phone numbers
Insurance policy
Guide book(s) covering the area you're visiting - it should include mammal/bird/reptile pages for easy identification
Your itinerary and reservation documents
Addresses and mobile numbers (postcards/e-mails/texts)
Any vaccinations certificates (where applicable)
Copy of your passport, kept in a separate place than your passport
Copy of marriage certificate, if applicable especially if you recently tied the knot