I really like Lost, but much like other shows it's not really a goto for survival information.

Food and water were addressed early on in the show, and all though they did build fire and shelter, it was relegated to a background activity that pretty much just happened for the most part.

Thank goodness Locke went a little overboard on the collection of knives he took with him for the "Walkabout". LOL

They do scavenge the aircraft quite a bit for equipment and show parts of the plane throughout the series, especially wiring used as ropes and ties. Items that various passengers had with them as carry on or in the luggage compartment are also used.

Though I've watched Lost since the beginning, I don't recall the exact timeline of events as related to seasons, so I'm trying to keep it light and not to spoil anything for you.

At some point a more permanent solution for food and shelter will show up. At first I thought it was a writing cop out, but it makes sense in the overall story line of the show.