Your character is stranded in a wood with no supplies, what can they use to survive? Your character is from the medieval times, how would they light a fire with no match? Your character is injured with no medical supplies? What can they do.
Below is a list of links that should help you with writing survival skills. It might not make you a survival expert but hopefully it will kickstart your research.
From reading these there are many different water collection techniques depending on the items you have to hand. If you have any type of bottle, jar or carton you can collect rain water. This is probably safer than getting it from a river or a lake. Once you have your water you need to decontaminate it as it could have dangerous micro organisms. Then you need to be careful to ration the water, especially if there are a few of you and you are leaving the source of water or you are relying on rain water.
Again with food you should only eat what you need and keep rations. Make it last as long as possible. Remember that you don’t have a fridge, so leave it too long and it is going to make you sick.
Making a Fire
How you build your fire is critically important, honest! Even with an ignition source such as fire lighters if you have a badly built fire it will struggle to start burning. Using a flint isn’t as easy as they make it look on TV. It is worth researching flints and how to obtain them in more detail.
Making and Finding suitable shelter
Exposure is more likely to kill than lack of water or food. If your character is exposed to the elements one of the first things they need to do is find shelter, especially if it is cold or the temperature is going to drop.
Other useful links
Hope these links help you guys out! It was fun to research this and I hope you find it as interesting as I did.