Basic rules to respect - having seen those come a cropper who didn't ...
DO respect the sun - this is tropical microwaving and do not initially expose yourself until after 4pm. Factor 50 recommended. And cover your head with a good white hat if you don't want blinding headaches.
DO take a roll of small bin bags - at any time a tropical shower can start and your western waterproof bag will offer woefully inadequate protection for your mobile and video camera. Plastic bags of all kinds come in useful.
DO take a plastic mac and plastic beach shoes for the same reason.
DO take a pocket torch and keep it with you. Lots of Seychelles roads are unlit and you see tourists hopping around with twisted ankles after they've fallen over in the pitch black. And night falls at around 7pm.
DO fall into conversation with the Seychellois. They are utterly charming and always gratified to talk about their beautiful islands.
DON'T drink the water unless you have an iron constitution. Bottled water is cheap and good. Fight shy of non boiled tap water served in tea in beach huts.
Is this your business?