If you arrived on an island by a raft or a boat, you can use it either to get back to a mainland if it is close by, or as a shelter to keep you dry and warm at night, and away from natural forces such as rain, high winds and sun.
You can build a shelter and prepare some food with a knife. Use your knife to cut branches, bamboo, thick grass and vines. Use it to make smaller pieces of wood that will help you start a fire. Attach your knife to a long stick with the help of vines or strong grass and use it as a spear to catch some fish. If you find coconuts, use your knife to make a hole to get some coconut water, which is rich in sugars and nutrients.
Carry waterproof matches with you at all times when traveling to remote places. These will allow you to build a fire that can be used to keep you warm, to cook any food from animals you might have caught, to boil ocean water to make it drinkable and to alert others that you need to be rescued if a boat or a plane passes nearby.
You will need to collect fresh water to stay hydrated while you are on a deserted island. Having an empty water bottle or any other type of container will help you catch fresh water from the rain or by making a solar water catcher. To make one, pick an area that is higher than the tide and that is exposed to sunlight the majority of the time. Dig a hole 3 feet deep and 3 feet wide. Place your container in the center of the hole. Place healthy green plants around the container and then put a plastic sheet or a plastic bag over the hole held safely in place by using rocks as weights. Put a small rock in the center of the plastic sheet and make a small hole. This will help water condensate and drip down into your container.
