Do your best not to litter.  Beach rubbish such as plastic containers takes years to bio-degrade.  Help prevent fragile environments from being polluted by asking if there are any recycling facilities available or alternatively, take rubbish home with you where practical.
Be careful with cigarettes and matches as they are often the cause of devastating forest fires.

Respect wild life reserves and, if there are any, stick to footpaths.
Respect local culture and observe dress codes if you visit religious sites.
Try to take an interest in the local community and speak a few words of the local language.

Ensure that the souvenirs you buy are not endangered species, such as coral, shells or hard woods.  This does not only contribute to the degradation of the natural environment and marine life but may be illegal.  Instead buy some unusual souvenirs from the local market – this will not only put money back into the community and help to preserve traditional lifestyles but also make for a different and interesting present for those back home! 

Not only does shopping from locally owned outlets and eating in local restaurants get you into the holiday spirit in a great way, it helps to put money back into the local community.  Additionally, this will ease pollution from air freighting food around the world, one of the most significant contributors to climate change.

Be respectful and always ask permission first if you want to photograph local people.

Haggling can be great fun but please remember that the small price you pay may be essential to the seller’s livelihood – pay a fair price!