Minecraft wiki entry for Beginner%27s_guide, associated text: Take any food or other resources from the chests. Some items like obsidian or horse armor may not be immediately useful, so you can leave those for later.
Collect any hay bales and harvest any crops that are ripe,. Try to replant what you harvest, but make sure you keep seeds for each of the four crops (wheat, carrots, potatoes, beetroot). If there are pumpkins or melons around, collect samples of those.
The hay bales can be turned into wheat, which, along with any harvested crops can be sold back to the farmers. If you have a fair bit of extra wood, and can find a Fletcher, you can turn the wood into sticks (see below) and sell those, getting 1 emerald for 2 logs' worth of wood. With those emeralds and any you find in the chests, you may be able to buy a couple more useful items, most likely leather armor or iron tools.
If you really need wood or stone, try harvesting a few logs or cobblestone from above head height in the houses, so as to minimize the damage.
Sleep in a bed overnight, and take it with you when you go.