Step 1: Choosing Materials
Choose any block that you can build on,and a slab. The type doesn't matter
Step 2: The Frame
Make a closed frame of any size.
Step 3: The Walls
Build up two more blocks to make the walls.
Step 4: The Roof
Make a roof of any kind.
Step 5: The Sniper's Hole
Cut out a hole in the front of your fort with at least one block on either side (see picture)
Step 6: The Slit
For the slit you'll need some slabs.Place them on the bottom half of your sniper hole.
Step 7: The Entrance
For the entrance you can put a door or a underground tunnel.
Step 8: Lighting
For lighting you could use torches or glow stone. Your choice.
Step 9: Storage
You could put a chest in the corner to store items such as bows,arrows,etc.
Step 10: "Hidy Hole"
You can make a "hidy hole" in the corner for protection in case things get rough.
Step 11: Finished Project
Now your sniper fort is done.Awesome accuracy inside,but hard to get hit inside.p.s. This structure is great for hunting mobs such as skeletons.