To remove air bubbles from wallpaper, you will need a wallpaper smoothing tool, a utility knife, and a pin or needle. First, use the smoothing tool to smooth out the bubble from the center towards the edges. If this does not work, use the pin or needle to puncture the bubble and gently push out the air with the smoothing tool. If the bubble is caused by excess adhesive, carefully lift the paper and apply more adhesive behind it, then smooth it out with the tool. Be careful not to damage the wallpaper while doing this.