The usual precautions are always advised.
It is better to travel in a group than alone. Have photocopies of your passport, tickets and credit cards in case the originals are lost.
Know the customs and conventions of your hosts. See your GP before departing as vaccinations may be recommended by some. The tap water is clean and safe in Vanuatu. Always eat and drink safely and wear clothing to decrease chances of being bitten by insects. Take plenty of appropriate sunscreen lotion.