1. Let the ceiling lead the way. Changing the shape of the ceiling can certainly make a big difference, especially as it emphasizes the linear quality of the space.
Even an asymmetrical ceiling leads us on, especially with light at the end. And adding an opening in the wall above the door to give us a hint of the beam helps reinforce the linear progression.
2. Turn up the lighting. Too much light can be softened with the use of a dimmer switch, while too little light can't be fixed easily.
3. What about that door? Use color to combine elements and create a pattern.
Or use a translucent material at the door to let light filter through while maintaining privacy.
Or better still, use a pocket door that disappears to reveal the window beyond.
4. Add a focal point. If the end of the hallway isn't a door or window but a blank wall, add some artwork to draw the viewer in.
And avoid the tunnel effect with some gentle natural light introduced from the side.
5. Place that special piece of furniture at the end. A place to rest and relax after that long journey down the gallery ...